# QNT 275 Entire Course

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QNT/275

STATISTICS FOR DECISION MAKING

The Latest Version A+ Study Guide

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QNT 275 Week 1 Statistics in Business

Purpose of Assignment

The purpose of this assignment is to have students demonstrate mastery of the foundational concepts that set the stage for the remainder of the course. Students apply those concepts to business research questions or problem situations to focus their thinking on statistical literacy for use in business decision-making.

Assignment Steps

Resources: Week 1 Readings; Statistics Lab

Tutorial help on Excel® and Word functions can be found on the Microsoft® Office® website. There are also additional tutorials via the web that offer support for office products.

Develop a 1,050-word response addressing each of the following prompts:

Define statistics with citation and reference.

Contrast quantitative data and qualitative data. Use two peer reviewed references.

Evaluate tables and charts used to represent quantitative and qualitative data.

Describe the levels of data measurement.

Describe the role of statistics in business decision-making.

Provide at least two business research questions, or problem situations, in which statistics was used or could be used.

Use two peer reviewed references.

Format your assignment consistent with APA guidelines.

Click the Assignment Files tab to submit your assignment.

QNT 275 Week 1 Practice Set

Complete the Week 1 Practice Set problems.

Click the Assignment Files tab to submit your assignment.

Practice Set 1

Practice Set 1

The following table lists the number of deaths by cause as reported by the Centers for Disease Control and Prevention on February 6, 2015:

Cause of Death

Number of Deaths

Heart disease

611,105

Cancer

584,881

Accidents

130,557

Stroke

128,978

Alzheimer’s disease

84,767

Diabetes

75,578

Influenza and Pneumonia

56,979

Suicide

41,149

What is the variable for this data set (use words)?

How many observations are in this data set (numeral)?

How many elements does this data set contain (numeral)?

Indicate which of the following variables are quantitative and which are qualitative.

Note: Spell quantitative and qualitative in lower case letters.

The amount of time a student spent studying for an exam

The amount of rain last year in 30 cities

The arrival status of an airline flight (early, on time, late, canceled) at an airport

A person’s blood type

The amount of gasoline put into a car at a gas station

A local gas station collected data from the day’s receipts, recording the gallons of gasoline each customer purchased. The following table lists the frequency distribution of the gallons of gas purchased by all customers on this one day at this gas station.

Gallons of Gas

Number of Customers

4 to less than 8

78

8 to less than 12

49

12 to less than 16

81

16 to less than 20

117

20 to less than 24

13

How many customers were served on this day at this gas station?

Find the class midpoints. Do all of the classes have the same width? If so, what is this width? If not, what are the different class widths?

What percentage of the customers purchased between 4 and 12 gallons? (do not include % sign. Round numerical value to one decimal place)

The following data give the one-way commuting times (in minutes) from home to work for a random sample of 50 workers.

23

17

34

26

18

33

46

42

12

37

44

15

22

19

28

32

18

39

40

48

16

11

9

24

18

26

31

7

30

15

18

22

29

32

30

21

19

14

26

37

25

36

23

39

42

46

29

17

24

31

What is the frequency for each class 0–9, 10–19, 20–29, 30–39, and 40–49.

Calculate the relative frequency and percentage for each class.

What percentage of the workers in this sample commute for 30 minutes or more?

Note: Round relative frequency to two decimal places. Complete the table by calculating the frequency, relative frequency, and percentage.

Commuting Times

Frequency

(part a)

Relative Frequency

(part c)

Percentage (%)

(part d)

0-9

?

0.??

?

10-19

?

0.??

?

20-29

?

0.??

?

30-39

?

0.??

?

40-49

?

0.??

?

The following data give the number of text messages sent on 40 randomly selected days during 2015 by a high school student.

32

33

33

34

35

36

37

37

37

37

38

39

40

41

41

42

42

42

43

44

44

45

45

45

47

47

47

47

47

48

48

49

50

50

51

52

53

54

59

61

Each stem has been displayed (left column). Complete this stem-and-leaf display for these data.

Note: Use a space in between each leaf. For example 1 2 3 4 5 6 7 8 9 (do not use this format 123456789).

3

?…

4

?…

5

?…

6

?…

6 A) Which of the five measures of center (the mean, the median, the trimmed mean, the weighted mean, and the mode) can be calculated for quantitative data only.

B) Which can be calculated for both quantitative and qualitative data?

Prices of cars have a distribution that is skewed to the right with outliers in the right tail. Which of the measures of center is the best to summarize this data set?

The following data give the amounts (in dollars) of electric bills for November 2015 for 12 randomly selected households selected from a small town.

205

265

176

314

243

192

297

357

238

281

342

259

Calculate the (a) mean, (b) median and (c) Is there a mode (Yes or No)?

The following data give the prices of seven textbooks randomly selected from a university bookstore.

$89

$170

$104

$113

$56

$161

$147

a) Find the mean for these data (input the numerical value without the dollar sign). Calculate the deviations of the data values from the mean.

b) Is the sum of these deviations zero (yes or no)?

c) Calculate the range (do not include unit).

d) Calculate the variance.

e) Calculate the standard deviation (round to one decimal place).

The following data give the speeds of 13 cars (in mph) measured by radar, traveling on I-84.

73

75

69

68

78

69

74

76

72

79

68

77

71

Find the values of the three quartiles and the interquartile range.

Calculate the (approximate) value of the 35th percentile (round to two decimal places).

Compute the percentile rank of 71 (round to two decimal places. Do not include the % symbol).

Note: Round to two decimal places. Do not include unit.

QNT 275 Week 1 Quiz

Your answers : 6/6 (100%)

Correct answerquestion1

Cross-section data are collected:

on different elements for the same variable for different periods of time

on the same variable for the same variable at different points in time

on different elements at the same point in time

for a qualitative variable

Correct answerquestion2

An independent group wants to determine if the consumption of gasoline has increased due to changes in price. The group randomly selects 320 gas stations from 12 different states and collects data from the month of the year when gas is the cheapest and from the month of the year when gas is the most expensive. The data shows no significant difference in gas consumption between the two months. In this example, what is the variable being studied?

The 320 gas stations chosen.

The price of gasoline.

The 12 different states.

The consumption of gasoline.

Correct answerquestion3

A simple random sample is a sample drawn in such a way that:

each member of the population has some chance of being included in the sample

each member of the population has a 0.10 chance for being included in the sample

each sample of the same size has an equal chance of being selected

every tenth element of an arranged population is included

Correct answerquestion4

The Ohio lottery involves selecting 5 numbers from 5 different bins. This is an example of sampling

with replacement.

without replacement.

Correct answerquestion5

In statistics, a population consists of:

a selection of a limited number of elements

all people living in the area under study

all people living in a country

all subjects or objects whose characteristics are being studied

Correct answerquestion6

Under inferential statistics, we study

the methods to make decisions about one or more populations based on sample results

how to make decisions about a mean, median, or mode

tables composed of summary measures

how a sample is taken from a population

QNT 275 Week 2 Individual Assignment Learning Team Charter

Resources: Week 2 Learning Team Collaborative Discussion and the Learning Team Charter for Collaborative Learning Activities.

Write a 150- to 200-word individual response to the following:

Consider the multiple definitions of collaboration.

Define collaboration and how you will apply it in this course based upon the discussion with your Learning Team. Be sure to reference and cite your sources.

Answer the question individually.

Click the Assignment Files tab to submit your assignment and be sure to attach a copy of your Learning Team Charter for Collaborative Learning Activities.

QNT 275 Week 2 Assignment Mini-Project 3-3

Purpose of Assignment

This assignment provided students with practice in understanding the relationship of averages and standard deviation to make an informed business decision about the gross income performance of each movie genre. Students will learn to implement the use of these statistical measures for better business decision-making.

Resources: Week 2 Videos; Week 2 Readings; Statistics Lab

Tutorial help on Excel® and Word functions can be found on the Microsoft® Office website. There are also additional tutorials via the web offering support for Office products.

Assignment Steps

Refer to Mini-Project Movie Data Set.

Analyze and write a report summarizing this data. This report should include answers to at least the following questions:

Calculate the summary measures (the mean, standard deviation, five-number summary, and interquartile range) of the total gross income for each movie genre.

Which genre had greater variability in total gross income? Explain why.

Draw a box-and-whisker plot of a movie’s length of time (minutes) by genre. Are there any differences in movie lengths when compared across genres? Are there any outliers?

Use the mean movie gross income for each genre to compare the movie opening gross income.

Choose an appropriate statistical measure to compare the consistency of movie gross income.

Make the calculations and write a 700-word report comparing the total movie gross income and the consistency of movie opening gross by genre.

Format your assignment consistent with APA guidelines.

Click the Assignment Files tab to submit your assignment.

QNT 275 Week 2 Practice Set

Practice Set 2

Practice Set 2

List the simple events for each of the following statistical experiments in a sample space.

One roll of a die.

Note: Separate your response with a comma (,). For example 22, 23, 24

Three tosses of a coin.

Note: Use this notation for your answer. heads = H. tails = T. For example HT, TH

One toss of a coin and one roll of a die.

Note: Use this notation. Heads = H or numbers 1, 2, 3, 4, 5, 6 for the dice. For example

H1 indicates heads and dice roll equal to 1.

Two students are randomly selected from a statistics class, and it is observed whether or not they suffer from math anxiety. Indicate which are simple and which are compound events.

Both students suffer from math anxiety.

Exactly one student suffers from math anxiety.

The first student does not suffer and the second suffers from math anxiety.

None of the students suffers from math anxiety.

A hat contains 40 marbles. Of them, 18 are red and 22 are green. If one marble is randomly selected out of this hat.

What is the probability that this marble is red (round to two decimal places)?

What is the probability that this marble is green (round to two decimal places?

Two thousand randomly selected adults were asked whether or not they have ever shopped on the Internet. The following table gives a two-way classification of the responses.

Have Shopped

Have Never Shopped

Male

500

700

Female

300

500

If one adult is selected at random from these 2000 adults, find the probability that this adult has never shopped on the Internet.

If one adult is selected at random from these 2000 adults, find the probability that this adult is a male.

If one adult is selected at random from these 2000 adults, find the probability that this adult has shopped on the Internet given that this adult is a female.

If one adult is selected at random from these 2000 adults, find the probability that this adult is a male given that this adult has never shopped on the Internet.

Find the joint probability of AAand BB for the following.

P(A)=.36and P(B|A)=.87

P(B)=.53and P(A|B)=.22

Classify each of the following random variables as discrete or continuous.

The time left on a parking meter

The number of bats broken by a major league baseball team in a season

The number of cars in a parking lot at a given time

The price of a car

The number of cars crossing a bridge on a given day

The time spent by a physician examining a patient

The number of books in a student’s bag

7. The following table gives the probability distribution of a discrete random variable x.

x

0

1

2

3

4

5

6

P(x)

.11

.19

.28

.15

.12

.09

.06

Find the following probabilities.

P(1≤x≤4)

Probability that xassumes a value less than 4.

Probability that xassumes a value greater than 2.

A limousine has eight tires on it. A fleet of such limos was fit with a batch of tires that mistakenly passed quality testing. The following table lists the probability distribution of the number of defective tires on this fleet of limos where xxrepresents the number of defective tires on a limo and P(x) is the corresponding probability.

x

0

1

2

3

4

5

6

7

8

P(x)

.0454

.1723

.2838

.2669

.1569

.0585

.0139

.0015

.0008

Calculate the mean and standard deviation of this probability distribution. Give a brief interpretation of the values of the mean and standard deviation.

Let xxbe a discrete random variable that possesses a binomial distribution. Using the binomial formula, find the following probabilities.

p(5) for n=8and p=.70

p(3) for n=4and p=.40

Verify your answers by using Table I of Appendix B.

Let xbe a discrete random variable that possesses a binomial distribution.

What is the mean (round to three decimal places)

What is the standard deviation of the probability distribution (round to three decimal places)?

QNT 275 Week 2 Quiz

Correct answerquestion1

The number of classes in a frequency distribution depends on the size of the data set. In general, the:

number of classes should be equal to the number of values in the data set divided by 5

larger the data set, the larger the number of classes

larger the data set, the smaller the number of classes

smaller the data set, the larger the number of classes

Correct answerquestion2

Which of the following pairs of events is mutually exclusive?

Female and male

Female and republican

Male and republican

Male and no opinion

Female and democrat

Ccrrect answerquestion3

Which of the following is not an example of a discrete random variable?

The number of persons allergic to penicillin

The time spent by a physician with a patient

The number of days it rains in a month in New York

The number of stocks a person owns

Ccrrect answerquestion4

We obtain the percentage of a category by:

dividing the frequency of that category by 100

dividing the sum of all frequencies by the frequency of that category

multiplying the frequency of that category by 100

multiplying the relative frequency of that category by 100

Ccrrect answerquestion5

You toss a coin nine times and observe 3 heads and 6 tails. This event is a:

compound event

multinomial sample point

multiple outcome

simple event

Ccrrect answerquestion6

You randomly select two households and observe whether or not they own a telephone answering machine. Which of the following is a simple event?

At most one of them owns a telephone answering machine.

Neither of the two owns a telephone answering machine.

At least one of them owns a telephone answering machine.

Exactly one of them owns a telephone answering machine.

QNT 275 Week 3 Business Decision Making Project Part 1

Purpose of Assignment

The purpose of this assignment is to provide students the opportunity to demonstrate mastery of their ability to apply statistical concepts to business situations to inform data-driven decision-making. The project is a 3-week project, with part 1 in Week 3, part 2 in Week 4, and part 3 in Week 5. In Week 3, students identify the organization, problem, research variable, methods for collecting data, and show mastery of validity and reliability as applied to data-collection methods.

Resources: Week 3 Videos; Week 3 Readings; Statistic Lab

Tutorial help on Excel® and Word functions can be found on the Microsoft® Office website. There are also additional tutorials via the web offering support for Office products.

Assignment Steps

Identify a business problem or opportunity at a company where you work or with which you are familiar. This will be a business problem you use for the individual assignments in Weeks 3-5. It should be a problem/opportunity for which gathering and analyzing some type of data would help you understand the problem/opportunity better.

Identify a research variable within the problem/opportunity that could be measured with some type of data collection.

Consider methods for collecting a suitable sample of either qualitative or quantitative data for the variable.

Consider how you will know if the data collection method would be valid and reliable.

Develop a 1,050-word analysis to describe a company, problem, and variable including the following in your submission:

Identify the name and description of the selected company.

Describe the problem at that company.

Identify one research variable from that problem. Describe the methods you would use for collecting a suitable sample of either qualitative or quantitative data for the variable (Note: do not actually collect any data).

Analyze how you will know if the data collection method would generate valid and reliable data (Note: do not actually collect any data).

Format your assignment consistent with APA guidelines.

Click the Assignment Files tab to submit your assignment.

QNT 275 Week 3 Practice Set

Complete the Week 3 Practice Set problems.

Click the Assignment Files tab to submit your assignment.

Practice Set 3

Practice Set 3

Let x be a continuous random variable. What is the probability that x assumes a single value, such as a (use numerical value)?

The following are the three main characteristics of a normal distribution.

The total area under a normal curve equals _____.

A normal curve is ___________ about the Consequently, 50% of the total area under a normal distribution curve lies on the left side of the mean, and 50% lies on the right side of the mean.

Fill in the blank. The tails of a normal distribution curve extend indefinitely in both directions without touching or crossing the horizontal Although a normal curve never meets the ________ axis, beyond the points represented by µ – 3σto µ+ 3σ it becomes so close to this axis that the area under the curve beyond these points in both directions is very close to zero.

For the standard normal distribution, find the area within one standard deviation of the

mean that is, the area between μ − σ and μ + σ. Round to four decimal places.

Find the area under the standard normal curve. Round to four decimal places.

between z = 0 and z = 1.95

between z = 0 and z = −2.05

between z = 1.15 and z = 2.37

from z = −1.53 to z = −2.88

from z = −1.67 to z = 2.24

The probability distribution of the population data is called the (1) Table 7.2 in the text provides an example of it. The probability distribution of a sample statistic is called its (2) _________. Table 7.5 in the text provides an example it.

Probability distribution

Population distribution

Normal distribution

Sampling distribution

___________ is the difference between the value of the sample statistic and the value of the corresponding population parameter, assuming that the sample is random and no non-sampling error has been made. Example 7–1 in the text displays sampling error. Sampling error occurs only in sample surveys.

Consider the following population of 10 numbers. 20 25 13 19 9 15 11 7 17 30

Find the population mean. Round to two decimal places.

Rich selected one sample of nine numbers from this population. The sample included the numbers 20, 25, 13, 9, 15, 11, 7, 17, and 30. Calculate sampling error for this sample. Round to decimal places.

Fill in the blank. The F distribution is ________ and skewed to the right. The F distribution has two numbers of degrees of freedom: df for the numerator and df for the denominator. The units of an F distribution, denoted by F, are nonnegative.

Find the critical value of F for the following. Round to two decimal places.

df = (3, 3) and area in the right tail = .05

df = (3, 10) and area in the right tail = .05

df = (3, 30) and area in the right tail = .05

The following ANOVA table, based on information obtained for three samples selected from three independent populations that are normally distributed with equal variances, has a few missing values.

Source of

Variation

Degrees of

Freedom

Sum of

Squares

Mean

Square

Value of the

Test Statistic

Between

2

II

19.2813

Within

89.3677

III

F = ___V__ = VII

VI

Total

12

IV

Find the missing values and complete the ANOVA table. Round to four decimal places.

Using α = .01, what is your conclusion for the test with the null hypothesis that the means of the three populations are all equal against the alternative hypothesis that the means of the three populations are not all equal?

Reject H0. Conclude that the means of the three populations are equal.

Reject H0. Conclude that the means of the three populations are not equal.

Do not reject H0. Conclude that the means of the three populations are equal.

Do not reject H0. Conclude that the means are of the three populations are not equal.

QNT 275 Week 3 Quiz

Your answers : 6/6 (100%)

Correct answerquestion1

The sampling error is:

an error that occurs when a sample of 30 or more members is drawn

the difference between the value of a sample statistic and the value of the corresponding population parameter

an error that occurs when a sample of fewer than 30 members is drawn

an error that occurs during collection, recording, and tabulation of data

Correct answerquestion2

To use an F distribution, the random variable must be:

a discrete random variable

a qualitative random variable

a continuous random variable

either a discrete or a continuous random variable

Correct answerquestion3

A continuous random variable is a random variable that can:

assume any value in one or more intervals

assume no continuous random frequency

have no random sample

assume only a countable set of values

Correct answerquestion4

The population distribution is the probability distribution of the:

whole population of a country

population data

population probabilities

population means

Correct answerquestion5

Which of the following is not a characteristic of the normal distribution?

The value of the mean is always greater than the value of the standard deviation

The two tails of the curve extend indefinitely

The total area under the curve is 1.0

The curve is symmetric about the mean

Correct answerquestion6

The units of an F distribution:

are always positive

are always nonnegative

can be negative, zero, or positive

are always negative

QNT 275 Week 4 Business Decision Making Project Part 2

Purpose of Assignment

This assignment provides students with practice in understanding how to develop a hypothesis and interpret its findings. Students will learn to implement the use of these statistical measures for better business decision-making.

Assignment Steps

Resources: Week 4 Videos; Week 4 Readings; Statistics Lab

Tutorial help on Excel® and Word functions can be found on the Microsoft® Office website. There are also additional tutorials via the web offering support for Office products.

Use the same business problem/opportunity and research variable you wrote about in Week 3.

Note: Do not actually collect any data; think hypothetically.

Develop a 1,050-word report in which you:

Identify which types of descriptive statistics might be best for summarizing the data, if you were to collect a sample.

Analyze which types of inferential statistics might be best for analyzing the data, if you were to collect a sample.

Analyze the role probability or trend analysis might play in helping address the business problem.

Analyze the role linear regression for trend analysis might play in helping address the business problem.

Analyze the role a time series might play in helping address the business problem.

Format your assignment consistent with APA guidelines.

Click the Assignment Files tab to submit your assignment.

QNT 275 Week 4 Practice Set

Complete the Week 4 Practice Set problems.

Click the Assignment Files tab to submit your assignment.

Practice Set 4

Practice Set 4

Find z for each of the following confidence levels. Round to two decimal places.

90%

95%

96%

97%

98%

99%

For a data set obtained from a random sample, n = 81 and x = 48.25. It is known

that σ = 4.8.

What is the point estimate of μ? Round to two decimal places

Make a 95% confidence interval for μ. What is the lower limit? Round to two decimal places.

Make a 95% confidence interval for μ. What is the upper limit? Round to two decimal places.

What is the margin of error of estimate for part b? Round to two decimal places.

Determine the sample size (nfor the estimate of μ for the following.

E = 2.3, σ = 15.40, confidence level = 99%. Round to the nearest whole number.

E = 4.1, σ = 23.45, confidence level = 95%. Round to the nearest whole number.

E = 25.9, σ = 122.25, confidence level = 90%. Round to the nearest whole number.

True or False.

a.The null hypothesis is a claim about a population parameter that is assumed to be false until it is declared false.

True

False

An alternative hypothesis is a claim about a population parameter that will be true if the null hypothesis is false.

True

False

The critical point(s) divide(s) is some of the area under a distribution curve into rejection and nonrejection regions.

True

False

The significance level, denoted by α, is the probability of making a Type II error, that is, the probability of rejecting the null hypothesis when it is actually true.

True

False

The nonrejection region is the area to the right or left of the critical point where the null hypothesis is not rejected.

True

False

You are given the null hypothesis. Select the correct alternative hypothesis.

H0: μ = 5 hours, what is H1?

left-tailed test

right-tailed test

two-tail test

H0: μ = $105, what is H1?

left-tailed test

right-tailed test

two-tail test

H0: μ = $47,000, what is H1?

left-tailed test

right-tailed test

two-tail test

H0: μ = 10 minutes, what is H1?

left-tailed test

right-tailed test

two-tail test

H0: μ = 30 hours, what is H1?

left-tailed test

right-tailed test

two-tail test

Fill in the blank. The level of significance in a test of hypothesis is the probability of making a ________. It is the area under the probability distribution curve where we reject H0.

Type I error

Type II error

Type III error

Consider H0: μ = 45 versus H1: μ < 45. A random sample of 25 observations produced a sample mean of 41.8. Using α = .025 and the population is known to be normally distributed with σ = 6.

What is the value of z? Round to two decimal places.

Would you reject the null hypothesis?

Reject Ho

Do not reject Ho

The following information is obtained from two independent samples selected from two normally distributed populations.

n1 = 18 x1 = 7.82 σ1 = 2.35

n2 =15 x2 =5.99 σ2 =3.17

What is the point estimate of μ1 − μ2? Round to two decimal places.

Construct a 99% confidence interval for μ1 − μ2. Find the margin of error for this estimate.

Round to two decimal places.

The following information is obtained from two independent samples selected from two

populations.

n1 =650 x1 =1.05 σ1 =5.22

n2 =675 x2 =1.54 σ2 =6.80

Test at a 5% significance level if μ1 is less than μ2.

Identify the appropriate distribution to use.

t distribution

normal distribution

What is the conclusion about the hypothesis?

Reject Ho

Do not reject Ho

Using data from the U.S. Census Bureau and other sources, www.nerdwallet.com estimated that considering only the households with credit card debts, the average credit card debt for U.S. house- holds was $15,523 in 2014 and $15,242 in 2013. Suppose that these estimates were based on random samples of 600 households with credit card debts in 2014 and 700 households with credit card debts in 2013. Suppose that the sample standard deviations for these two samples were $3870 and $3764, respectively. Assume that the standard deviations for the two populations are unknown but equal.

Let μ1 and μ2 be the average credit card debts for all such households for the years 2014 and 2013, respectively. What is the point estimate of μ1 − μ2? Round to two decimal places. Do not include the dollar sign.

Construct a 98% confidence interval for μ1 − μ2. Round to two decimal places. Do not include the dollar sign.

What is the lower bound? Round to two decimal places.

What is the upper bound? Round to two decimal places.

Using a 1% significance level, can you conclude that the average credit card debt for such households was higher in 2014 than in 2013? Use both the p-value and the critical-value approaches to make this test.

Reject Ho

Do not reject Ho

QNT 275 Week 4 Quiz

Your answers : 6/6 (100%)

Correct answerquestion1

The values assigned to a population parameter based on the value(s) of a sample statistic are:

a sampling distribution

the probability distribution

the probabilities

estimate(s)

Correct answerquestion2

The null hypothesis is a claim about a:

statistic, where the claim is assumed to be true until it is declared false

parameter, where the claim is assumed to be true until it is declared false

parameter, where the claim is assumed to be false until it is declared true

statistic, where the claim is assumed to be false until it is declared true

Correct answerquestion3

A sample of 126 corporate managers and another sample of 168 college professors produced mean job-related stress scores of 7.35 for the managers and 6.86 for the professors. Suppose that the standard deviations of the stress scores are 1.12 for the managers and 1.82 for the professors. The null hypothesis is that the mean stress scores are the same for corporate managers and college professors, while the alternative hypothesis is that the mean stress score for managers is different from the mean stress score for professors. The significance level for the test is 1%. What are the critical values of z?

-2.58 and 2.58

-1.96 and 1.96

-3.09 and 3.09

-2.33 and 2.33

Correct answerquestion4

Two samples drawn from two populations are independent if:

the selection of one sample from a population is not related to the selection of the second sample from the same population

the selection of one sample from one population does not affect the selection of the second sample from the second population

two samples selected from the same population have no relation

the selection of one sample from a population is related to the selection of the second sample from the same population

Correct answerquestion5

The confidence level of an interval estimate is denoted by:

β

(1-α)*100%

(1-β)*100%

α

Correct answerquestion6

For a two-tailed test, the p-value is:

the area in the tail under the curve on the side which the sample statistic lies

twice the area under the curve between the mean and the observed value of the sample statistic

twice the area in the tail under the curve on the side which the sample statistic lies

the area under the curve between the mean and the observed value of the sample statistic

QNT 275 Week 5 Signature Assignment: Business Decision Making Project Part 3

Purpose of Assignment

This assignment provides students with practice in understanding when or why ANOVA and linear regression are identified based on parameters. Students will learn to implement these statistical measures for better business decision-making.

Assignment Steps

Resources: Week 5 Videos; Week 5 Readings; Statistics Lab

Tutorial help on Excel® and Word functions can be found on the Microsoft® Office website. There are also additional tutorials via the web offering support for Office products.

Prepare an 11- to 15-slide Microsoft® PowerPoint® presentation for the senior management team based on the business problem or opportunity you described in Weeks 3-4.

Include on the slides what you would want the audience to see (include appropriate visual aids/layout) and include in the speaker’s notes section what you would say as you present each slide. If any source material is quoted or paraphrased in the presentation, use APA citations and references.

Draw on material you developed in the Week’s 3 and 4 assignments.

Include the following in your presentation:

Introduction slide

Agenda slide

Describe the organization, with a brief description

Explain the business problem or opportunity

Describe the hypothesis

Analyze why the business problem is important

Identify what variable would be best to measure for this problem and explain why

Identify statistical methods used to analyze data

Apply data analysis techniques to this problem (tell which techniques should be used: descriptive statistics, inferential stats, probability) and explain why

Apply a possible solution to the problem/opportunity, with rationale

Evaluate how data could be used to measure the implementation of such a solution

Conclusion

Reference slide (if any source material is quoted or paraphrased throughout the presentation)

Format your assignment consistent with APA guidelines.

Click the Assignment Files tab to submit your assignment.

QNT 275 Week 5 Practice Set

Complete the Week 5 Practice Set problems.

Click the Assignment Files tab to submit your assignment.

Practice Set 5

Practice Set 5

This distribution has only one parameter. The curve is skewed to the right for small df and

becomes symmetric for large df. The entire distribution curve lies to the right of the vertical

axis. The distribution assumes nonnegative values only

t distribution

Normal distribution

Chi-square distribution

Linear regression.

Find the value of x2 for 12 degrees of freedom and an area of .025 in the right tail of the chi-

square distribution curve. What is the value of chi-square? Round to three decimal places

Determine the value of x2 for 14 degrees of freedom and an area of .10 in the left tail of the

chi-square distribution curve. What is the value of chi-square? Round to three decimal places

Determine the value of x2 for 23 degrees of freedom and an area of .990 in the left tail of the

chi-square distribution curve. What is the value of chi-square? Round to three decimal places.

Α ____________ compares the observed frequencies from a multinomial experiment with

expected frequencies derived from a certain pattern or theoretical distribution. The test

evaluates how well the observed frequencies fit the expected frequencies.

Goodness-of-fit test

Chi-square test

Linear regression

The __________ are the frequencies obtained from the performance of a

multinomial experiment. The expected frequencies are the frequencies that we expect to obtain

if the null hypothesis is true.

Observed frequencies

Expected frequencies

Fluctuating frequencies

The expected frequency of a category is given by Ε = np where n is the sample size and p is the

probability that an element belongs to that category if the null hypothesis is true. The

________ for a goodness–of–fit test are k – 1, where k denotes the number of possible

outcomes (or categories) for the experiment.

Number of observations

Degrees of freedom

Total population

This model includes only two variables, one independent and one dependent, is called a _____1______. The ___2____ is the one being explained, and the ___3___ is the one used to explain the variation in the dependent Select the correct letter that would make the sentence true.

Select a letter from the list to make this statement true.

Select a letter from the list to make this statement true.

Select a letter from the list to make this statement true.

Linear model

Qualitative variable

Multivariate analysis of variance

Independent variable

Simple regression model

One-way Analysis of Variance

Dependent variable

Quantitative variable

A population data set produced the following information.

N=460, ∑x=3920, ∑y=2650, ∑xy=26,570, ∑x2=48,530

Find the population regression line. Round to three decimal places. Use the format as an example when submitting your equation 456.123 + 789.123x

The following information is obtained from a sample data set.

n=12, ∑x=66, ∑y=588, ∑xy=2244, ∑x2=396

Find the estimated regression line Use this format as an example when submitting your equation 123 – 45x

QNT 275 Week 5 Final Exam

Complete the Final Examination. You are allowed one attempt to complete the examination, which is timed and must be completed in 3 hours. Results are automatically graded and sent to your instructor.

Note: The automated final exam was designed in Google Chrome and is best viewed in the latest version of the browser. If you do not use the latest version of Google Chrome to view and complete the automated final exam, you may not be able to view the entire exam content. If you do not have the most current version of Google Chrome, download the browser before you enter the exam.

1

To make tests of hypotheses about more than two population means, we use the:

t distribution

normal distribution

chi-square distribution

analysis of variance distribution

2

You randomly select two households and observe whether or not they own a telephone answering machine. Which of the following is a simple event?

At most one of them owns a telephone answering machine.

At least one of them owns a telephone answering machine.

Neither of the two owns a telephone answering machine.

Exactly one of them owns a telephone answering machine.

3

In a one-way ANOVA, we analyze only one:

population

mean

variable

sample

4

The regression model y = A + Bx + e is:

an exact relationship

a probabilistic model

a nonlinear model

a deterministic model

5

For a goodness-of-fit test, the frequencies obtained from the performance of an experiment are the:

objective frequencies

observed frequencies

subjective frequencies

expected frequencies

6

The mean of a discrete random variable is the mean of its:

frequency distribution

second and third quartiles

percentage distribution

probability distribution

7

A researcher wants to test if the mean annual salary of all lawyers in a city is different than $110,000. The null hypothesis for this example will be that the population mean is:

greater than to $110,000

not equal to $110,000

equal to $110,000

less than to $110,000

8

Which of the following pairs of events are mutually exclusive?

Female and no

Female and yes

Female and male

No and yes

9

In a hypothesis test, a Type I error occurs when:

a false null hypothesis is not rejected

a true null hypothesis is rejected

a true null hypothesis is not rejected

a false null hypothesis is rejected

10

You toss a coin nine times and observe 3 heads and 6 tails. This event is a:

multiple outcome

simple event

multinomial sample point

compound event

11

The graph of a cumulative frequency distribution is a(n):

stem-and-leaf display

frequency histogram

ogive

line graph

12

What is the critical value of t for the hypothesis test?

2.441

2.449

2.733

2.738

13

An error that occurs because of chance is called:

mean error

probability error

sampling error

nonsampling error

14

A researcher wants to test if elementary school children spend less than 30 minutes per day on homework. The alternative hypothesis for this example will be that the population mean is:

equal to 30 minutes

not equal to 30 minutes

less than or equal to 30 minutes

less than 30 minutes

15

A quantitative variable is the only type of variable that can:

have no intermediate values

be used to prepare tables

assume numeric values for which arithmetic operations make sense

be graphed

16

The p-value is the:

largest significance level at which the alternative hypothesis can be rejected

smallest significance level at which the null hypothesis can be rejected

largest significance level at which the null hypothesis can be rejected

smallest significance level at which the null hypothesis can be rejected

17

If you divide the number of elements in a sample with a specific characteristic by the total number of elements in the sample, the dividend is the:

sampling distribution

sample distribution

sample mean

sample proportion

18

A linear regression:

gives a relationship between two variables that can be described by a line

gives a relationship between two variables that cannot be described by a line

gives a relationship between three variables that can be described by a line

contains only two variables

19A continuous random variable x has a right-skewed distribution with a mean of 80 and a standard deviation of 12. The sampling distribution of the sample mean for a sample of 50 elements taken from this population is:

skewed to the left

not normal

approximately normal

skewed to the right

20

Which of the following assumptions is not required to use ANOVA?

All samples are of the same size.

The samples drawn from different populations are random and independent.

The populations from which the samples are drawn are (approximately) normally distributed.

The populations from which the samples are drawn have the same variance.

21

The model y = A + Bx is a:

nonlinear model

stochastic model

probabilistic model

deterministic model

22

In a hypothesis test, a Type II error occurs when:

a false null hypothesis is rejected

a true null hypothesis is rejected

a true null hypothesis is not rejected

a false null hypothesis is not rejected

23

Two paired or matched samples would imply that:

data are collected on two variables from the elements of two independent samples

two data values are collected from the same source (elements) for two dependent samples

two data values are collected from the same source (elements) for two independent samples

data are collected on one variable from the elements of two independent samples

24

What is the critical value of z for the hypothesis test?

-2.05

-2.33

-2.17

-1.96

25

A qualitative variable is the only type of variable that:

can assume an uncountable set of values

cannot be measured numerically

cannot be graphed

can assume numerical values

26

The alternative hypothesis is a claim about a:

statistic, where the claim is assumed to be false until it is declared true

parameter, where the claim is assumed to be true until it is declared false

statistic, where the claim is assumed to be true if the null hypothesis is declared false

parameter, where the claim is assumed to be true if the null hypothesis is declared false

27

For small degrees of freedom, the chi-square distribution is:

rectangular

skewed to the left

symmetric

skewed to the right

28

We can use the analysis of variance procedure to test hypotheses about:

the proportion of one population

two or more population proportions

two or more population means

the mean of one population

29

For a one-tailed test, the p-value is:

twice the area under the curve to the same side of the value of the sample statistic as is specified in the alternative hypothesis

the area under the curve to the same side of the value of the sample statistic as is specified in the alternative hypothesis

twice the area under the curve between the mean and the observed value of the sample statistic

the area under the curve between the mean and the observed value of the sample statistic

30

The mean of a discrete random variable is its:

second quartile

box-and-whisker measure

upper hinge

expected value

https://zh.scribd.com/document/340327850/Uop-Tutorial

QNT/275

STATISTICS FOR DECISION MAKING

The Latest Version A+ Study Guide

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Entire Course Link

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QNT 275 Week 1 Statistics in Business

Purpose of Assignment

The purpose of this assignment is to have students demonstrate mastery of the foundational concepts that set the stage for the remainder of the course. Students apply those concepts to business research questions or problem situations to focus their thinking on statistical literacy for use in business decision-making.

Assignment Steps

Resources: Week 1 Readings; Statistics Lab

Tutorial help on Excel® and Word functions can be found on the Microsoft® Office® website. There are also additional tutorials via the web that offer support for office products.

Develop a 1,050-word response addressing each of the following prompts:

Define statistics with citation and reference.

Contrast quantitative data and qualitative data. Use two peer reviewed references.

Evaluate tables and charts used to represent quantitative and qualitative data.

Describe the levels of data measurement.

Describe the role of statistics in business decision-making.

Provide at least two business research questions, or problem situations, in which statistics was used or could be used.

Use two peer reviewed references.

Format your assignment consistent with APA guidelines.

Click the Assignment Files tab to submit your assignment.

QNT 275 Week 1 Practice Set

Complete the Week 1 Practice Set problems.

Click the Assignment Files tab to submit your assignment.

Practice Set 1

Practice Set 1

The following table lists the number of deaths by cause as reported by the Centers for Disease Control and Prevention on February 6, 2015:

Cause of Death

Number of Deaths

Heart disease

611,105

Cancer

584,881

Accidents

130,557

Stroke

128,978

Alzheimer’s disease

84,767

Diabetes

75,578

Influenza and Pneumonia

56,979

Suicide

41,149

What is the variable for this data set (use words)?

How many observations are in this data set (numeral)?

How many elements does this data set contain (numeral)?

Indicate which of the following variables are quantitative and which are qualitative.

Note: Spell quantitative and qualitative in lower case letters.

The amount of time a student spent studying for an exam

The amount of rain last year in 30 cities

The arrival status of an airline flight (early, on time, late, canceled) at an airport

A person’s blood type

The amount of gasoline put into a car at a gas station

A local gas station collected data from the day’s receipts, recording the gallons of gasoline each customer purchased. The following table lists the frequency distribution of the gallons of gas purchased by all customers on this one day at this gas station.

Gallons of Gas

Number of Customers

4 to less than 8

78

8 to less than 12

49

12 to less than 16

81

16 to less than 20

117

20 to less than 24

13

How many customers were served on this day at this gas station?

Find the class midpoints. Do all of the classes have the same width? If so, what is this width? If not, what are the different class widths?

What percentage of the customers purchased between 4 and 12 gallons? (do not include % sign. Round numerical value to one decimal place)

The following data give the one-way commuting times (in minutes) from home to work for a random sample of 50 workers.

23

17

34

26

18

33

46

42

12

37

44

15

22

19

28

32

18

39

40

48

16

11

9

24

18

26

31

7

30

15

18

22

29

32

30

21

19

14

26

37

25

36

23

39

42

46

29

17

24

31

What is the frequency for each class 0–9, 10–19, 20–29, 30–39, and 40–49.

Calculate the relative frequency and percentage for each class.

What percentage of the workers in this sample commute for 30 minutes or more?

Note: Round relative frequency to two decimal places. Complete the table by calculating the frequency, relative frequency, and percentage.

Commuting Times

Frequency

(part a)

Relative Frequency

(part c)

Percentage (%)

(part d)

0-9

?

0.??

?

10-19

?

0.??

?

20-29

?

0.??

?

30-39

?

0.??

?

40-49

?

0.??

?

The following data give the number of text messages sent on 40 randomly selected days during 2015 by a high school student.

32

33

33

34

35

36

37

37

37

37

38

39

40

41

41

42

42

42

43

44

44

45

45

45

47

47

47

47

47

48

48

49

50

50

51

52

53

54

59

61

Each stem has been displayed (left column). Complete this stem-and-leaf display for these data.

Note: Use a space in between each leaf. For example 1 2 3 4 5 6 7 8 9 (do not use this format 123456789).

3

?…

4

?…

5

?…

6

?…

6 A) Which of the five measures of center (the mean, the median, the trimmed mean, the weighted mean, and the mode) can be calculated for quantitative data only.

B) Which can be calculated for both quantitative and qualitative data?

Prices of cars have a distribution that is skewed to the right with outliers in the right tail. Which of the measures of center is the best to summarize this data set?

The following data give the amounts (in dollars) of electric bills for November 2015 for 12 randomly selected households selected from a small town.

205

265

176

314

243

192

297

357

238

281

342

259

Calculate the (a) mean, (b) median and (c) Is there a mode (Yes or No)?

The following data give the prices of seven textbooks randomly selected from a university bookstore.

$89

$170

$104

$113

$56

$161

$147

a) Find the mean for these data (input the numerical value without the dollar sign). Calculate the deviations of the data values from the mean.

b) Is the sum of these deviations zero (yes or no)?

c) Calculate the range (do not include unit).

d) Calculate the variance.

e) Calculate the standard deviation (round to one decimal place).

The following data give the speeds of 13 cars (in mph) measured by radar, traveling on I-84.

73

75

69

68

78

69

74

76

72

79

68

77

71

Find the values of the three quartiles and the interquartile range.

Calculate the (approximate) value of the 35th percentile (round to two decimal places).

Compute the percentile rank of 71 (round to two decimal places. Do not include the % symbol).

Note: Round to two decimal places. Do not include unit.

QNT 275 Week 1 Quiz

Your answers : 6/6 (100%)

Correct answerquestion1

Cross-section data are collected:

on different elements for the same variable for different periods of time

on the same variable for the same variable at different points in time

on different elements at the same point in time

for a qualitative variable

Correct answerquestion2

An independent group wants to determine if the consumption of gasoline has increased due to changes in price. The group randomly selects 320 gas stations from 12 different states and collects data from the month of the year when gas is the cheapest and from the month of the year when gas is the most expensive. The data shows no significant difference in gas consumption between the two months. In this example, what is the variable being studied?

The 320 gas stations chosen.

The price of gasoline.

The 12 different states.

The consumption of gasoline.

Correct answerquestion3

A simple random sample is a sample drawn in such a way that:

each member of the population has some chance of being included in the sample

each member of the population has a 0.10 chance for being included in the sample

each sample of the same size has an equal chance of being selected

every tenth element of an arranged population is included

Correct answerquestion4

The Ohio lottery involves selecting 5 numbers from 5 different bins. This is an example of sampling

with replacement.

without replacement.

Correct answerquestion5

In statistics, a population consists of:

a selection of a limited number of elements

all people living in the area under study

all people living in a country

all subjects or objects whose characteristics are being studied

Correct answerquestion6

Under inferential statistics, we study

the methods to make decisions about one or more populations based on sample results

how to make decisions about a mean, median, or mode

tables composed of summary measures

how a sample is taken from a population

QNT 275 Week 2 Individual Assignment Learning Team Charter

Resources: Week 2 Learning Team Collaborative Discussion and the Learning Team Charter for Collaborative Learning Activities.

Write a 150- to 200-word individual response to the following:

Consider the multiple definitions of collaboration.

Define collaboration and how you will apply it in this course based upon the discussion with your Learning Team. Be sure to reference and cite your sources.

Answer the question individually.

Click the Assignment Files tab to submit your assignment and be sure to attach a copy of your Learning Team Charter for Collaborative Learning Activities.

QNT 275 Week 2 Assignment Mini-Project 3-3

Purpose of Assignment

This assignment provided students with practice in understanding the relationship of averages and standard deviation to make an informed business decision about the gross income performance of each movie genre. Students will learn to implement the use of these statistical measures for better business decision-making.

Resources: Week 2 Videos; Week 2 Readings; Statistics Lab

Tutorial help on Excel® and Word functions can be found on the Microsoft® Office website. There are also additional tutorials via the web offering support for Office products.

Assignment Steps

Refer to Mini-Project Movie Data Set.

Analyze and write a report summarizing this data. This report should include answers to at least the following questions:

Calculate the summary measures (the mean, standard deviation, five-number summary, and interquartile range) of the total gross income for each movie genre.

Which genre had greater variability in total gross income? Explain why.

Draw a box-and-whisker plot of a movie’s length of time (minutes) by genre. Are there any differences in movie lengths when compared across genres? Are there any outliers?

Use the mean movie gross income for each genre to compare the movie opening gross income.

Choose an appropriate statistical measure to compare the consistency of movie gross income.

Make the calculations and write a 700-word report comparing the total movie gross income and the consistency of movie opening gross by genre.

Format your assignment consistent with APA guidelines.

Click the Assignment Files tab to submit your assignment.

QNT 275 Week 2 Practice Set

Practice Set 2

Practice Set 2

List the simple events for each of the following statistical experiments in a sample space.

One roll of a die.

Note: Separate your response with a comma (,). For example 22, 23, 24

Three tosses of a coin.

Note: Use this notation for your answer. heads = H. tails = T. For example HT, TH

One toss of a coin and one roll of a die.

Note: Use this notation. Heads = H or numbers 1, 2, 3, 4, 5, 6 for the dice. For example

H1 indicates heads and dice roll equal to 1.

Two students are randomly selected from a statistics class, and it is observed whether or not they suffer from math anxiety. Indicate which are simple and which are compound events.

Both students suffer from math anxiety.

Exactly one student suffers from math anxiety.

The first student does not suffer and the second suffers from math anxiety.

None of the students suffers from math anxiety.

A hat contains 40 marbles. Of them, 18 are red and 22 are green. If one marble is randomly selected out of this hat.

What is the probability that this marble is red (round to two decimal places)?

What is the probability that this marble is green (round to two decimal places?

Two thousand randomly selected adults were asked whether or not they have ever shopped on the Internet. The following table gives a two-way classification of the responses.

Have Shopped

Have Never Shopped

Male

500

700

Female

300

500

If one adult is selected at random from these 2000 adults, find the probability that this adult has never shopped on the Internet.

If one adult is selected at random from these 2000 adults, find the probability that this adult is a male.

If one adult is selected at random from these 2000 adults, find the probability that this adult has shopped on the Internet given that this adult is a female.

If one adult is selected at random from these 2000 adults, find the probability that this adult is a male given that this adult has never shopped on the Internet.

Find the joint probability of AAand BB for the following.

P(A)=.36and P(B|A)=.87

P(B)=.53and P(A|B)=.22

Classify each of the following random variables as discrete or continuous.

The time left on a parking meter

The number of bats broken by a major league baseball team in a season

The number of cars in a parking lot at a given time

The price of a car

The number of cars crossing a bridge on a given day

The time spent by a physician examining a patient

The number of books in a student’s bag

7. The following table gives the probability distribution of a discrete random variable x.

x

0

1

2

3

4

5

6

P(x)

.11

.19

.28

.15

.12

.09

.06

Find the following probabilities.

P(1≤x≤4)

Probability that xassumes a value less than 4.

Probability that xassumes a value greater than 2.

A limousine has eight tires on it. A fleet of such limos was fit with a batch of tires that mistakenly passed quality testing. The following table lists the probability distribution of the number of defective tires on this fleet of limos where xxrepresents the number of defective tires on a limo and P(x) is the corresponding probability.

x

0

1

2

3

4

5

6

7

8

P(x)

.0454

.1723

.2838

.2669

.1569

.0585

.0139

.0015

.0008

Calculate the mean and standard deviation of this probability distribution. Give a brief interpretation of the values of the mean and standard deviation.

Let xxbe a discrete random variable that possesses a binomial distribution. Using the binomial formula, find the following probabilities.

p(5) for n=8and p=.70

p(3) for n=4and p=.40

Verify your answers by using Table I of Appendix B.

Let xbe a discrete random variable that possesses a binomial distribution.

What is the mean (round to three decimal places)

What is the standard deviation of the probability distribution (round to three decimal places)?

QNT 275 Week 2 Quiz

Correct answerquestion1

The number of classes in a frequency distribution depends on the size of the data set. In general, the:

number of classes should be equal to the number of values in the data set divided by 5

larger the data set, the larger the number of classes

larger the data set, the smaller the number of classes

smaller the data set, the larger the number of classes

Correct answerquestion2

Which of the following pairs of events is mutually exclusive?

Female and male

Female and republican

Male and republican

Male and no opinion

Female and democrat

Ccrrect answerquestion3

Which of the following is not an example of a discrete random variable?

The number of persons allergic to penicillin

The time spent by a physician with a patient

The number of days it rains in a month in New York

The number of stocks a person owns

Ccrrect answerquestion4

We obtain the percentage of a category by:

dividing the frequency of that category by 100

dividing the sum of all frequencies by the frequency of that category

multiplying the frequency of that category by 100

multiplying the relative frequency of that category by 100

Ccrrect answerquestion5

You toss a coin nine times and observe 3 heads and 6 tails. This event is a:

compound event

multinomial sample point

multiple outcome

simple event

Ccrrect answerquestion6

You randomly select two households and observe whether or not they own a telephone answering machine. Which of the following is a simple event?

At most one of them owns a telephone answering machine.

Neither of the two owns a telephone answering machine.

At least one of them owns a telephone answering machine.

Exactly one of them owns a telephone answering machine.

QNT 275 Week 3 Business Decision Making Project Part 1

Purpose of Assignment

The purpose of this assignment is to provide students the opportunity to demonstrate mastery of their ability to apply statistical concepts to business situations to inform data-driven decision-making. The project is a 3-week project, with part 1 in Week 3, part 2 in Week 4, and part 3 in Week 5. In Week 3, students identify the organization, problem, research variable, methods for collecting data, and show mastery of validity and reliability as applied to data-collection methods.

Resources: Week 3 Videos; Week 3 Readings; Statistic Lab

Tutorial help on Excel® and Word functions can be found on the Microsoft® Office website. There are also additional tutorials via the web offering support for Office products.

Assignment Steps

Identify a business problem or opportunity at a company where you work or with which you are familiar. This will be a business problem you use for the individual assignments in Weeks 3-5. It should be a problem/opportunity for which gathering and analyzing some type of data would help you understand the problem/opportunity better.

Identify a research variable within the problem/opportunity that could be measured with some type of data collection.

Consider methods for collecting a suitable sample of either qualitative or quantitative data for the variable.

Consider how you will know if the data collection method would be valid and reliable.

Develop a 1,050-word analysis to describe a company, problem, and variable including the following in your submission:

Identify the name and description of the selected company.

Describe the problem at that company.

Identify one research variable from that problem. Describe the methods you would use for collecting a suitable sample of either qualitative or quantitative data for the variable (Note: do not actually collect any data).

Analyze how you will know if the data collection method would generate valid and reliable data (Note: do not actually collect any data).

Format your assignment consistent with APA guidelines.

Click the Assignment Files tab to submit your assignment.

QNT 275 Week 3 Practice Set

Complete the Week 3 Practice Set problems.

Click the Assignment Files tab to submit your assignment.

Practice Set 3

Practice Set 3

Let x be a continuous random variable. What is the probability that x assumes a single value, such as a (use numerical value)?

The following are the three main characteristics of a normal distribution.

The total area under a normal curve equals _____.

A normal curve is ___________ about the Consequently, 50% of the total area under a normal distribution curve lies on the left side of the mean, and 50% lies on the right side of the mean.

Fill in the blank. The tails of a normal distribution curve extend indefinitely in both directions without touching or crossing the horizontal Although a normal curve never meets the ________ axis, beyond the points represented by µ – 3σto µ+ 3σ it becomes so close to this axis that the area under the curve beyond these points in both directions is very close to zero.

For the standard normal distribution, find the area within one standard deviation of the

mean that is, the area between μ − σ and μ + σ. Round to four decimal places.

Find the area under the standard normal curve. Round to four decimal places.

between z = 0 and z = 1.95

between z = 0 and z = −2.05

between z = 1.15 and z = 2.37

from z = −1.53 to z = −2.88

from z = −1.67 to z = 2.24

The probability distribution of the population data is called the (1) Table 7.2 in the text provides an example of it. The probability distribution of a sample statistic is called its (2) _________. Table 7.5 in the text provides an example it.

Probability distribution

Population distribution

Normal distribution

Sampling distribution

___________ is the difference between the value of the sample statistic and the value of the corresponding population parameter, assuming that the sample is random and no non-sampling error has been made. Example 7–1 in the text displays sampling error. Sampling error occurs only in sample surveys.

Consider the following population of 10 numbers. 20 25 13 19 9 15 11 7 17 30

Find the population mean. Round to two decimal places.

Rich selected one sample of nine numbers from this population. The sample included the numbers 20, 25, 13, 9, 15, 11, 7, 17, and 30. Calculate sampling error for this sample. Round to decimal places.

Fill in the blank. The F distribution is ________ and skewed to the right. The F distribution has two numbers of degrees of freedom: df for the numerator and df for the denominator. The units of an F distribution, denoted by F, are nonnegative.

Find the critical value of F for the following. Round to two decimal places.

df = (3, 3) and area in the right tail = .05

df = (3, 10) and area in the right tail = .05

df = (3, 30) and area in the right tail = .05

The following ANOVA table, based on information obtained for three samples selected from three independent populations that are normally distributed with equal variances, has a few missing values.

Source of

Variation

Degrees of

Freedom

Sum of

Squares

Mean

Square

Value of the

Test Statistic

Between

2

II

19.2813

Within

89.3677

III

F = ___V__ = VII

VI

Total

12

IV

Find the missing values and complete the ANOVA table. Round to four decimal places.

Using α = .01, what is your conclusion for the test with the null hypothesis that the means of the three populations are all equal against the alternative hypothesis that the means of the three populations are not all equal?

Reject H0. Conclude that the means of the three populations are equal.

Reject H0. Conclude that the means of the three populations are not equal.

Do not reject H0. Conclude that the means of the three populations are equal.

Do not reject H0. Conclude that the means are of the three populations are not equal.

QNT 275 Week 3 Quiz

Your answers : 6/6 (100%)

Correct answerquestion1

The sampling error is:

an error that occurs when a sample of 30 or more members is drawn

the difference between the value of a sample statistic and the value of the corresponding population parameter

an error that occurs when a sample of fewer than 30 members is drawn

an error that occurs during collection, recording, and tabulation of data

Correct answerquestion2

To use an F distribution, the random variable must be:

a discrete random variable

a qualitative random variable

a continuous random variable

either a discrete or a continuous random variable

Correct answerquestion3

A continuous random variable is a random variable that can:

assume any value in one or more intervals

assume no continuous random frequency

have no random sample

assume only a countable set of values

Correct answerquestion4

The population distribution is the probability distribution of the:

whole population of a country

population data

population probabilities

population means

Correct answerquestion5

Which of the following is not a characteristic of the normal distribution?

The value of the mean is always greater than the value of the standard deviation

The two tails of the curve extend indefinitely

The total area under the curve is 1.0

The curve is symmetric about the mean

Correct answerquestion6

The units of an F distribution:

are always positive

are always nonnegative

can be negative, zero, or positive

are always negative

QNT 275 Week 4 Business Decision Making Project Part 2

Purpose of Assignment

This assignment provides students with practice in understanding how to develop a hypothesis and interpret its findings. Students will learn to implement the use of these statistical measures for better business decision-making.

Assignment Steps

Resources: Week 4 Videos; Week 4 Readings; Statistics Lab

Tutorial help on Excel® and Word functions can be found on the Microsoft® Office website. There are also additional tutorials via the web offering support for Office products.

Use the same business problem/opportunity and research variable you wrote about in Week 3.

Note: Do not actually collect any data; think hypothetically.

Develop a 1,050-word report in which you:

Identify which types of descriptive statistics might be best for summarizing the data, if you were to collect a sample.

Analyze which types of inferential statistics might be best for analyzing the data, if you were to collect a sample.

Analyze the role probability or trend analysis might play in helping address the business problem.

Analyze the role linear regression for trend analysis might play in helping address the business problem.

Analyze the role a time series might play in helping address the business problem.

Format your assignment consistent with APA guidelines.

Click the Assignment Files tab to submit your assignment.

QNT 275 Week 4 Practice Set

Complete the Week 4 Practice Set problems.

Click the Assignment Files tab to submit your assignment.

Practice Set 4

Practice Set 4

Find z for each of the following confidence levels. Round to two decimal places.

90%

95%

96%

97%

98%

99%

For a data set obtained from a random sample, n = 81 and x = 48.25. It is known

that σ = 4.8.

What is the point estimate of μ? Round to two decimal places

Make a 95% confidence interval for μ. What is the lower limit? Round to two decimal places.

Make a 95% confidence interval for μ. What is the upper limit? Round to two decimal places.

What is the margin of error of estimate for part b? Round to two decimal places.

Determine the sample size (nfor the estimate of μ for the following.

E = 2.3, σ = 15.40, confidence level = 99%. Round to the nearest whole number.

E = 4.1, σ = 23.45, confidence level = 95%. Round to the nearest whole number.

E = 25.9, σ = 122.25, confidence level = 90%. Round to the nearest whole number.

True or False.

a.The null hypothesis is a claim about a population parameter that is assumed to be false until it is declared false.

True

False

An alternative hypothesis is a claim about a population parameter that will be true if the null hypothesis is false.

True

False

The critical point(s) divide(s) is some of the area under a distribution curve into rejection and nonrejection regions.

True

False

The significance level, denoted by α, is the probability of making a Type II error, that is, the probability of rejecting the null hypothesis when it is actually true.

True

False

The nonrejection region is the area to the right or left of the critical point where the null hypothesis is not rejected.

True

False

You are given the null hypothesis. Select the correct alternative hypothesis.

H0: μ = 5 hours, what is H1?

left-tailed test

right-tailed test

two-tail test

H0: μ = $105, what is H1?

left-tailed test

right-tailed test

two-tail test

H0: μ = $47,000, what is H1?

left-tailed test

right-tailed test

two-tail test

H0: μ = 10 minutes, what is H1?

left-tailed test

right-tailed test

two-tail test

H0: μ = 30 hours, what is H1?

left-tailed test

right-tailed test

two-tail test

Fill in the blank. The level of significance in a test of hypothesis is the probability of making a ________. It is the area under the probability distribution curve where we reject H0.

Type I error

Type II error

Type III error

Consider H0: μ = 45 versus H1: μ < 45. A random sample of 25 observations produced a sample mean of 41.8. Using α = .025 and the population is known to be normally distributed with σ = 6.

What is the value of z? Round to two decimal places.

Would you reject the null hypothesis?

Reject Ho

Do not reject Ho

The following information is obtained from two independent samples selected from two normally distributed populations.

n1 = 18 x1 = 7.82 σ1 = 2.35

n2 =15 x2 =5.99 σ2 =3.17

What is the point estimate of μ1 − μ2? Round to two decimal places.

Construct a 99% confidence interval for μ1 − μ2. Find the margin of error for this estimate.

Round to two decimal places.

The following information is obtained from two independent samples selected from two

populations.

n1 =650 x1 =1.05 σ1 =5.22

n2 =675 x2 =1.54 σ2 =6.80

Test at a 5% significance level if μ1 is less than μ2.

Identify the appropriate distribution to use.

t distribution

normal distribution

What is the conclusion about the hypothesis?

Reject Ho

Do not reject Ho

Using data from the U.S. Census Bureau and other sources, www.nerdwallet.com estimated that considering only the households with credit card debts, the average credit card debt for U.S. house- holds was $15,523 in 2014 and $15,242 in 2013. Suppose that these estimates were based on random samples of 600 households with credit card debts in 2014 and 700 households with credit card debts in 2013. Suppose that the sample standard deviations for these two samples were $3870 and $3764, respectively. Assume that the standard deviations for the two populations are unknown but equal.

Let μ1 and μ2 be the average credit card debts for all such households for the years 2014 and 2013, respectively. What is the point estimate of μ1 − μ2? Round to two decimal places. Do not include the dollar sign.

Construct a 98% confidence interval for μ1 − μ2. Round to two decimal places. Do not include the dollar sign.

What is the lower bound? Round to two decimal places.

What is the upper bound? Round to two decimal places.

Using a 1% significance level, can you conclude that the average credit card debt for such households was higher in 2014 than in 2013? Use both the p-value and the critical-value approaches to make this test.

Reject Ho

Do not reject Ho

QNT 275 Week 4 Quiz

Your answers : 6/6 (100%)

Correct answerquestion1

The values assigned to a population parameter based on the value(s) of a sample statistic are:

a sampling distribution

the probability distribution

the probabilities

estimate(s)

Correct answerquestion2

The null hypothesis is a claim about a:

statistic, where the claim is assumed to be true until it is declared false

parameter, where the claim is assumed to be true until it is declared false

parameter, where the claim is assumed to be false until it is declared true

statistic, where the claim is assumed to be false until it is declared true

Correct answerquestion3

A sample of 126 corporate managers and another sample of 168 college professors produced mean job-related stress scores of 7.35 for the managers and 6.86 for the professors. Suppose that the standard deviations of the stress scores are 1.12 for the managers and 1.82 for the professors. The null hypothesis is that the mean stress scores are the same for corporate managers and college professors, while the alternative hypothesis is that the mean stress score for managers is different from the mean stress score for professors. The significance level for the test is 1%. What are the critical values of z?

-2.58 and 2.58

-1.96 and 1.96

-3.09 and 3.09

-2.33 and 2.33

Correct answerquestion4

Two samples drawn from two populations are independent if:

the selection of one sample from a population is not related to the selection of the second sample from the same population

the selection of one sample from one population does not affect the selection of the second sample from the second population

two samples selected from the same population have no relation

the selection of one sample from a population is related to the selection of the second sample from the same population

Correct answerquestion5

The confidence level of an interval estimate is denoted by:

β

(1-α)*100%

(1-β)*100%

α

Correct answerquestion6

For a two-tailed test, the p-value is:

the area in the tail under the curve on the side which the sample statistic lies

twice the area under the curve between the mean and the observed value of the sample statistic

twice the area in the tail under the curve on the side which the sample statistic lies

the area under the curve between the mean and the observed value of the sample statistic

QNT 275 Week 5 Signature Assignment: Business Decision Making Project Part 3

Purpose of Assignment

This assignment provides students with practice in understanding when or why ANOVA and linear regression are identified based on parameters. Students will learn to implement these statistical measures for better business decision-making.

Assignment Steps

Resources: Week 5 Videos; Week 5 Readings; Statistics Lab

Tutorial help on Excel® and Word functions can be found on the Microsoft® Office website. There are also additional tutorials via the web offering support for Office products.

Prepare an 11- to 15-slide Microsoft® PowerPoint® presentation for the senior management team based on the business problem or opportunity you described in Weeks 3-4.

Include on the slides what you would want the audience to see (include appropriate visual aids/layout) and include in the speaker’s notes section what you would say as you present each slide. If any source material is quoted or paraphrased in the presentation, use APA citations and references.

Draw on material you developed in the Week’s 3 and 4 assignments.

Include the following in your presentation:

Introduction slide

Agenda slide

Describe the organization, with a brief description

Explain the business problem or opportunity

Describe the hypothesis

Analyze why the business problem is important

Identify what variable would be best to measure for this problem and explain why

Identify statistical methods used to analyze data

Apply data analysis techniques to this problem (tell which techniques should be used: descriptive statistics, inferential stats, probability) and explain why

Apply a possible solution to the problem/opportunity, with rationale

Evaluate how data could be used to measure the implementation of such a solution

Conclusion

Reference slide (if any source material is quoted or paraphrased throughout the presentation)

Format your assignment consistent with APA guidelines.

Click the Assignment Files tab to submit your assignment.

QNT 275 Week 5 Practice Set

Complete the Week 5 Practice Set problems.

Click the Assignment Files tab to submit your assignment.

Practice Set 5

Practice Set 5

This distribution has only one parameter. The curve is skewed to the right for small df and

becomes symmetric for large df. The entire distribution curve lies to the right of the vertical

axis. The distribution assumes nonnegative values only

t distribution

Normal distribution

Chi-square distribution

Linear regression.

Find the value of x2 for 12 degrees of freedom and an area of .025 in the right tail of the chi-

square distribution curve. What is the value of chi-square? Round to three decimal places

Determine the value of x2 for 14 degrees of freedom and an area of .10 in the left tail of the

chi-square distribution curve. What is the value of chi-square? Round to three decimal places

Determine the value of x2 for 23 degrees of freedom and an area of .990 in the left tail of the

chi-square distribution curve. What is the value of chi-square? Round to three decimal places.

Α ____________ compares the observed frequencies from a multinomial experiment with

expected frequencies derived from a certain pattern or theoretical distribution. The test

evaluates how well the observed frequencies fit the expected frequencies.

Goodness-of-fit test

Chi-square test

Linear regression

The __________ are the frequencies obtained from the performance of a

multinomial experiment. The expected frequencies are the frequencies that we expect to obtain

if the null hypothesis is true.

Observed frequencies

Expected frequencies

Fluctuating frequencies

The expected frequency of a category is given by Ε = np where n is the sample size and p is the

probability that an element belongs to that category if the null hypothesis is true. The

________ for a goodness–of–fit test are k – 1, where k denotes the number of possible

outcomes (or categories) for the experiment.

Number of observations

Degrees of freedom

Total population

This model includes only two variables, one independent and one dependent, is called a _____1______. The ___2____ is the one being explained, and the ___3___ is the one used to explain the variation in the dependent Select the correct letter that would make the sentence true.

Select a letter from the list to make this statement true.

Select a letter from the list to make this statement true.

Select a letter from the list to make this statement true.

Linear model

Qualitative variable

Multivariate analysis of variance

Independent variable

Simple regression model

One-way Analysis of Variance

Dependent variable

Quantitative variable

A population data set produced the following information.

N=460, ∑x=3920, ∑y=2650, ∑xy=26,570, ∑x2=48,530

Find the population regression line. Round to three decimal places. Use the format as an example when submitting your equation 456.123 + 789.123x

The following information is obtained from a sample data set.

n=12, ∑x=66, ∑y=588, ∑xy=2244, ∑x2=396

Find the estimated regression line Use this format as an example when submitting your equation 123 – 45x

QNT 275 Week 5 Final Exam

Complete the Final Examination. You are allowed one attempt to complete the examination, which is timed and must be completed in 3 hours. Results are automatically graded and sent to your instructor.

Note: The automated final exam was designed in Google Chrome and is best viewed in the latest version of the browser. If you do not use the latest version of Google Chrome to view and complete the automated final exam, you may not be able to view the entire exam content. If you do not have the most current version of Google Chrome, download the browser before you enter the exam.

1

To make tests of hypotheses about more than two population means, we use the:

t distribution

normal distribution

chi-square distribution

analysis of variance distribution

2

You randomly select two households and observe whether or not they own a telephone answering machine. Which of the following is a simple event?

At most one of them owns a telephone answering machine.

At least one of them owns a telephone answering machine.

Neither of the two owns a telephone answering machine.

Exactly one of them owns a telephone answering machine.

3

In a one-way ANOVA, we analyze only one:

population

mean

variable

sample

4

The regression model y = A + Bx + e is:

an exact relationship

a probabilistic model

a nonlinear model

a deterministic model

5

For a goodness-of-fit test, the frequencies obtained from the performance of an experiment are the:

objective frequencies

observed frequencies

subjective frequencies

expected frequencies

6

The mean of a discrete random variable is the mean of its:

frequency distribution

second and third quartiles

percentage distribution

probability distribution

7

A researcher wants to test if the mean annual salary of all lawyers in a city is different than $110,000. The null hypothesis for this example will be that the population mean is:

greater than to $110,000

not equal to $110,000

equal to $110,000

less than to $110,000

8

Which of the following pairs of events are mutually exclusive?

Female and no

Female and yes

Female and male

No and yes

9

In a hypothesis test, a Type I error occurs when:

a false null hypothesis is not rejected

a true null hypothesis is rejected

a true null hypothesis is not rejected

a false null hypothesis is rejected

10

You toss a coin nine times and observe 3 heads and 6 tails. This event is a:

multiple outcome

simple event

multinomial sample point

compound event

11

The graph of a cumulative frequency distribution is a(n):

stem-and-leaf display

frequency histogram

ogive

line graph

12

What is the critical value of t for the hypothesis test?

2.441

2.449

2.733

2.738

13

An error that occurs because of chance is called:

mean error

probability error

sampling error

nonsampling error

14

A researcher wants to test if elementary school children spend less than 30 minutes per day on homework. The alternative hypothesis for this example will be that the population mean is:

equal to 30 minutes

not equal to 30 minutes

less than or equal to 30 minutes

less than 30 minutes

15

A quantitative variable is the only type of variable that can:

have no intermediate values

be used to prepare tables

assume numeric values for which arithmetic operations make sense

be graphed

16

The p-value is the:

largest significance level at which the alternative hypothesis can be rejected

smallest significance level at which the null hypothesis can be rejected

largest significance level at which the null hypothesis can be rejected

smallest significance level at which the null hypothesis can be rejected

17

If you divide the number of elements in a sample with a specific characteristic by the total number of elements in the sample, the dividend is the:

sampling distribution

sample distribution

sample mean

sample proportion

18

A linear regression:

gives a relationship between two variables that can be described by a line

gives a relationship between two variables that cannot be described by a line

gives a relationship between three variables that can be described by a line

contains only two variables

19A continuous random variable x has a right-skewed distribution with a mean of 80 and a standard deviation of 12. The sampling distribution of the sample mean for a sample of 50 elements taken from this population is:

skewed to the left

not normal

approximately normal

skewed to the right

20

Which of the following assumptions is not required to use ANOVA?

All samples are of the same size.

The samples drawn from different populations are random and independent.

The populations from which the samples are drawn are (approximately) normally distributed.

The populations from which the samples are drawn have the same variance.

21

The model y = A + Bx is a:

nonlinear model

stochastic model

probabilistic model

deterministic model

22

In a hypothesis test, a Type II error occurs when:

a false null hypothesis is rejected

a true null hypothesis is rejected

a true null hypothesis is not rejected

a false null hypothesis is not rejected

23

Two paired or matched samples would imply that:

data are collected on two variables from the elements of two independent samples

two data values are collected from the same source (elements) for two dependent samples

two data values are collected from the same source (elements) for two independent samples

data are collected on one variable from the elements of two independent samples

24

What is the critical value of z for the hypothesis test?

-2.05

-2.33

-2.17

-1.96

25

A qualitative variable is the only type of variable that:

can assume an uncountable set of values

cannot be measured numerically

cannot be graphed

can assume numerical values

26

The alternative hypothesis is a claim about a:

statistic, where the claim is assumed to be false until it is declared true

parameter, where the claim is assumed to be true until it is declared false

statistic, where the claim is assumed to be true if the null hypothesis is declared false

parameter, where the claim is assumed to be true if the null hypothesis is declared false

27

For small degrees of freedom, the chi-square distribution is:

rectangular

skewed to the left

symmetric

skewed to the right

28

We can use the analysis of variance procedure to test hypotheses about:

the proportion of one population

two or more population proportions

two or more population means

the mean of one population

29

For a one-tailed test, the p-value is:

twice the area under the curve to the same side of the value of the sample statistic as is specified in the alternative hypothesis

the area under the curve to the same side of the value of the sample statistic as is specified in the alternative hypothesis

twice the area under the curve between the mean and the observed value of the sample statistic

the area under the curve between the mean and the observed value of the sample statistic

30

The mean of a discrete random variable is its:

second quartile

box-and-whisker measure

upper hinge

expected value

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