# QNT 351 Entire Course

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QNT 351 Week 1 Connect Problem Set
1.
Which of the following is an example of a continuous variable?
Tons of concrete to complete a parking garage
Number of students in a statistics class
Zip codes of shoppers
Rankings of baseball teams in a league

2.
The incomes of 50 loan applicants are obtained. Which level of measurement is income?
Nominal
Ordinal
Interval
Ratio

3.
The members of each basketball team wear numbers on their jerseys. What scale of measurement are these numbers considered?
Nominal
Ordinal
Interval
Ratio

4
The reported unemployment is 5.5% of the population. What measurement scale is used to measure unemployment?
Nominal
Ordinal
Interval or ratio
Descriptive
5.
The Nielsen Ratings break down the number of people watching a particular television show by age. What level of measurement is age?
Nominal
Ordinal
Interval
Ratio
6.

An example of a qualitative variable is _________________.
Number of children in a family
Weight of a person
Color of ink in a pen
Miles between oil changes
7.

Two thousand one hundred and forty frequent business travelers are asked which midwestern city they prefer: Indianapolis, Saint Louis, Chicago, or Milwaukee. 180 liked Indianapolis best, 460 liked Saint Louis, 1240 liked Chicago, and the remainder preferred Milwaukee. Develop a frequency table and a relative frequency table to summarize this information. (Round relative frequency to 3 decimal places.)

City

Frequency

Relative Frequency

Indianapolis

St. Louis

Chicago

Milwaukee

8.

The Cambridge Power and Light Company selected a random sample of 20 residential customers. Following are the amounts, to the nearest dollar, the customers were charged for electrical service last month:

9.

Consider these five values a population: 6, 3, 5, 3, and 6.

a.

Determine the mean of the population. (Round your answer to 1 decimal place.)

b.

Determine the variance of the population. (Round your answer to 2 decimal places.)

10.

An investor buys 100 shares of AT&T stock and records its price change daily. Which concept of probability would you use to estimate the probability of an individual event?

Probability of an individual event

Empirical
Classical

QNT 351 Week 2 Connect Problem Set
1. Award: 10 out of 10.00 points

The director of admissions at Kinzua University in Nova Scotia estimated the distribution of student admissions for the fall semester on the basis of past experience.

Probability

1.

What is the expected number of admissions for the fall semester?

2.

Compute the variance and the standard deviation of the number of admissions. (Round your standard deviation to 2 decimal places.)

Variance

Standard deviation

2.Award: 10 out of 10.00 points

The Internal Revenue Service is studying the category of charitable contributions. A sample of 26 returns is selected from young couples between the ages of 20 and 35 who had an adjusted gross income of more than \$100,000. Of these 26 returns, 6 had charitable contributions of more than \$1,000. Suppose 5 of these returns are selected for a comprehensive audit.

a

You should use the hypergeometric distribution is appropriate. Because

b.

What is the probability exactly one of the five audited had a charitable deduction of more than \$1,000? (Round your answer to 4 decimal places.)

Probability

c.

What is the probability at least one of the audited returns had a charitable contribution of more than \$1,000? (Round your answer to 4 decimal places.)

Probability

3.Award: 10 out of 10.00 points

According to the “January theory,” if the stock market is up for the month of January, it will be up for the year. If it is down in January, it will be down for the year. According to an article in The Wall Street Journal, this theory held for x out of the last x years. Suppose there is no truth to this theory; that is, the probability it is either up or down is 0.5.

What is the probability this could occur by chance? (Round your answer to 6 decimal places.)

Probability

4.Award: 10 out of 10.00 points

Customers experiencing technical difficulty with their internet cable hookup may call an 800 number for technical support. It takes the technician between x seconds and x minutes to resolve the problem. The distribution of this support time follows the uniform distribution.

a.

What are the values for a and b in minutes? (Do not round your intermediate calculations. Round your answers to 1 decimal place.)

a

b

b-1.

What is the mean time to resolve the problem? (Do not round your intermediate calculations. Round your answer to 2 decimal places.)

Mean

b-2.

What is the standard deviation of the time? (Do not round your intermediate calculations. Round your answer to 2 decimal places.)

Standard deviation

c.

What percent of the problems take more than 5 minutes to resolve? (Do not round your intermediate calculations. Round your answer to 2 decimal places.)

Percent

d.

Suppose we wish to find the middle 50% of the problem-solving times. What are the end points of these two times? (Do not round your intermediate calculations. Round your answers to 3 decimal places.)

End point 1

End point 2

5.Award: 10 out of 10.00 points

A normal population has a mean of 20 and a standard deviation of 5.

a.

Compute the z value associated with 24. (Round your answer to 2 decimal places.)

Z

b.

What proportion of the population is between 20 and 24? (Round  z-score computation to 2 decimal places and your final answer to 4 decimal places.)

Proportion

c.

What proportion of the population is less than 18? (Round z-score computation to 2 decimal places and your final answer to 4 decimal places.)

Proportion

6.Award: 10 out of 10.00 points

Assume that the hourly cost to operate a commercial airplane follows the normal distribution with a mean of \$x per hour and a standard deviation of \$x.

What is the operating cost for the lowest x% of the airplanes? (Round z value to 2 decimal places and round final answer to nearest whole dollar.)

Operating cost

7.Award: 10 out of 10.00 points

The manufacturer of a laser printer reports the mean number of pages a cartridge will print before it needs replacing is x. The distribution of pages printed per cartridge closely follows the normal probability distribution and the standard deviation is x pages. The manufacturer wants to provide guidelines to potential customers as to how long they can expect a cartridge to last.

How many pages should the manufacturer advertise for each cartridge if it wants to be correct 99 percent of the time? (Round z value to 2 decimal places. Round your answer to the nearest whole number.)

Pages

8.Award: 8 out of 10.00 points

A study of long-distance phone calls made from General Electric Corporate Headquarters in Fairfield, Connecticut, revealed the length of the calls, in minutes, follows the normal probability distribution. The mean length of time per call was 4.90 minutes and the standard deviation was 0.40 minutes.

a.

What fraction of the calls last between 4.90 and 5.60 minutes? (Round z-score computation to 2 decimal places and your final answer to 4 decimal places.)

Fraction of calls

b.

What fraction of the calls last more than 5.60 minutes? (Round z-score computation to 2 decimal places and your final answer to 4 decimal places.)

Fraction of calls

c.

What fraction of the calls last between 5.60 and 6.50 minutes? (Round z-score computation to 2 decimal places and your final answer to 4 decimal places.)

Fraction of calls

d.

What fraction of the calls last between 4.50 and 6.50 minutes? (Round z-score computation to 2 decimal places and your final answer to 4 decimal places.)

Fraction of calls

e.

As part of her report to the president, the director of communications would like to report the length of the longest (in duration) 5 percent of the calls. What is this time? (Round z-score computation to 2 decimal places and your final answer to 2 decimal places.)

Duration

9.Award: 10 out of 10.00 points

A population consists of the following five values:xxx, x x, and x.

a.

List all samples of size 3, and compute the mean of each sample. (Round your mean value to 2 decimal places.)

Sample

Values

Sum

Mean

b.

Compute the mean of the distribution of sample means and the population mean. (Round your answers to 2 decimal places.)

Sample means

Population mean

10.Award: 10 out of 10.00 points

The mean age at which men in the United States marry for the first time follows the normal distribution with a mean of 24.1 years. The standard deviation of the distribution is 2.5 years.

For a random sample of 66 men, what is the likelihood that the age at which they were married for the first time is less than 24.6 years? (Round z value to 2 decimal places. Round your answer to 4 decimal places.)

Probability

QNT 351 Week 2 LT Assignments
Chapter 1
4.     For each of the following, determine whether the group is a sample or a population.
5.     The participants in a study of a new cholesterol drug.
6.     The drivers who received a speeding ticket in Kansas City last month.
7.     Those on welfare in Cook County (Chicago), Illinois.
8.     The 30 stocks reported as a part of the Dow Jones Industrial Average.
8.     For the following questions, would you collect information using a sample or a population?
Why?
1.     Statistics 201 is a course taught at a university. Professor A. Verage has taught nearly1,500 students in the course over the past 5 years. You would like to know the averagegrade for the course.
2.     As part of a research project, you need to report the average profitability of the numberone corporation in the Fortune 500 for the past 10 years.
3.     You are looking forward to graduation and your first job as a salesperson for one offive large pharmaceutical corporations. Planning for your interviews, you will need toknow about each company’s mission, profitability, products, and markets.
4.     You are shopping for a new MP3 music player such as the Apple iPod. The manufacturersadvertise the number of music tracks that can be stored in the memory. Usually,the advertisers assume relatively short, popular music to estimate the number oftracks that can be stored. You, however, like Broadway musical tunes and they aremuch longer. You would like to estimate how many Broadway tunes will fit on yourMP3 player.

12.  Utilize the concepts of sample and population to describe how a presidential election isunlike an “exit” poll of the electorate.
16.  AVX Stereo Equipment, Inc., recently began a “no-hassles” return policy. A sample of500 customers who had recently returned items showed 400 thought the policy wasfair, 32 thought it took too long to complete the transaction, and the rest had no opinion.
On the basis of this information, make an inference about customer reaction to thenew policy
18.  The following chart depicts the average amounts spent by consumers on holiday gifts.
Write a brief report summarizing the amounts spent during the holidays. Be sure toinclude the total amount spent, and the percent spent by each group.

QNT 351 Week 3 Connect Problem Set
Score:70/70Points100%

1.

A sample of 43 observations is selected from a normal population. The sample mean is 30, and the population standard deviation is 3. Conduct the following test of hypothesis using the 0.05 significance level.

H0 : μ ≤ 29

H1 : μ 29

a.

Is this a one- or two-tailed test?

b.

What is the decision rule? (Round your answer to 3 decimal places.)

c.

What is the value of the test statistic? (Round your answer to 2 decimal places.)

d.

What is your decision regarding H0?

e.

p-value

2.

At the time she was hired as a server at the Grumney Family Restaurant, Beth Brigden was told, “You can average \$86 a day in tips.” Assume the population of daily tips is normally distributed with a standard deviation of \$3.81. Over the first 48 days she was employed at the restaurant, the mean daily amount of her tips was \$87.07. At the 0.02 significance level, can Ms. Brigden conclude that her daily tips average more than \$86?

a.

State the null hypothesis and the alternate hypothesis.

b.

State the decision rule.

c.

Compute the value of the test statistic. (Round your answer to 2 decimal places.)

Value of the test statistic

d.

What is your decision regarding H0?

e.

3.

The Rocky Mountain district sales manager of Rath Publishing Inc., a college textbook publishing company, claims that the sales representatives make an average of 43 sales calls per week on professors. Several reps say that this estimate is too low. To investigate, a random sample of 41 sales representatives reveals that the mean number of calls made last week was 44. The standard deviation of the sample is 2.9 calls. Using the 0.100 significance level, can we conclude that the mean number of calls per salesperson per week is more than 43?

H0 : μ ≤ 43

H1 : μ 43

1.

Compute the value of the test statistic. (Round your answer to 3 decimal places.)

Value of the test statistic

2.

What is your decision regarding H0?

4.

A United Nations report shows the mean family income for Mexican migrants to the United States is \$27,150 per year. A FLOC (Farm Labor Organizing Committee) evaluation of 30 Mexican family units reveals a mean to be \$29,500 with a sample standard deviation of \$11,150. Does this information disagree with the United Nations report? Apply the 0.01 significance level.

a.

State the null hypothesis and the alternate hypothesis.

H0: μ =

H1: μ ≠

b.

State the decision rule for .01 significance level. (Negative amounts should be indicated by a minus sign. Round your answers to 3 decimal places.)

c.

Compute the value of the test statistic. (Round your answer to 2 decimal places.)

Value of the test statistic

d.

Does this information disagree with the United Nations report? Apply the 0.01 significance level.

5.

he following information is available.

H0 : μ ≥ 220

H1 : μ < 220

A sample of 64 observations is selected from a normal population. The sample mean is 215, and the population standard deviation is 15. Conduct the following test of hypothesis using the .025 significance level.

a.

Is this a one- or two-tailed test?

b.

What is the decision rule? (Negative amount should be indicated by a minus sign. Round your answer to 2 decimal places.)

c.

What is the value of the test statistic? (Negative amount should be indicated by a minus sign. Round your answer to 3 decimal places.)

d.

What is your decision regarding H0?

e.

6.

Given the following hypotheses:

H0 : μ ≤ 10

H1 : μ 10

A random sample of 10 observations is selected from a normal population. The sample mean was 12 and the sample standard deviation 3. Using the .05 significance level:

a.

Reject H0 if t

b.

Compute the value of the test statistic. (Round your answer to 3 decimal places.)

Value of the test statistic

c.

What is your decision regarding the null hypothesis?

Given the following hypotheses:

H0 : μ = 400

H1 : μ ≠ 400

A random sample of 12 observations is selected from a normal population. The sample mean was 407 and the sample standard deviation 6. Using the .01 significance level:

a.

State the decision rule. (Negative amount should be indicated by a minus sign. Round your answers to 3 decimal places.)

b.

Compute the value of the test statistic. (Round your answer to 3 decimal places.)

Value of the test statistic

c.

What is your decision regarding the null hypothesis?

QNT 351 Week 3 LT Assignment
1.     The events and are mutually exclusive. Suppose P(X) _ .05 and P(Y) _ .02. What isthe probability of either or occurring? What is the probability that neither nor willhappen?

2.     Let P(X) _ .55 and P(Y) _ .35. Assume the probability that they both occur is .20. Whatis the probability of either or occurring?

3.     Suppose P(X1) = .75 and P(Y2|X1) = .40. What is the joint probability of X1 and Y2?

4.     Refer to the following table.

1.     Determine P(A1).
2.     Determine P(B1|A2).
3.     Determine P(B2 and A3).

5.     Berdine’s Chicken Factory has several stores in the Hilton Head, South Carolina, area. Wheninterviewing applicants for server positions, the owner would like to include information onthe amount of tip a server can expect to earn per check (or bill). A study of 500 recentchecks indicated the server earned the following amounts in tips per 8-hour shift.

Amount of Tip Number
\$0 up to \$ 20 200
20 up to 50 100
50 up to 100 75
100 up to 200 75
200 or more 50
Total 500

1.     What is the probability of a tip of \$200 or more?
2.     Are the categories “\$0 up to \$20,” “\$20 up to \$50,” and so on considered mutuallyexclusive?
3.     If the probabilities associated with each outcome were totaled, what would that total be?
4.     What is the probability of a tip of up to \$50?
5.     What is the probability of a tip of less than \$200?

QNT 351 Week 4 Connect Problem Set
1.

The production department of Celltronics International wants to explore the relationship between the number of employees who assemble a subassembly and the number produced. As an experiment, 2 employees were assigned to assemble the subassemblies. They produced 6 during a one-hour period. Then 4 employees assembled them. They produced 10 during a one-hour period. The complete set of paired observations follows.

Number of
Assemblers

One-Hour
Production (units)

2

6

4

10

1

4

5

18

3

12

The dependent variable is production; that is, it is assumed that different levels of production result from a different number of employees.

b.

A scatter diagram is provided below. Based on it, does there appear to be any relationship between the number of assemblers and production?

, as the number of assemblers

, so does the production.

c.

Compute the correlation coefficient. (Negative amounts should be indicated by a minus sign. Round sx, sy and r to 3 decimal places.)

X

Y

( )2

( )2

( )( )

2

6

-4

16

4

10

1

1

0

1

4

-6

36

5

18

2

4

16

3

12

2

0

0

=

=

sx

=

sy

=

r

=

2.
value:
1.00 points

The following sample observations were randomly selected. (Round your answers to 2 decimal places.)

X:

4

5

3

6

10

Y:

9.8

10.6

9

16.4

19.6

a.

The regression equation is   = + X

b.

When X is 7 this gives =

3.
value:
10.00 points

Bi-lo Appliance Super-Store has outlets in several large metropolitan areas in New England. The general sales manager aired a commercial for a digital camera on selected local TV stations prior to a sale starting on Saturday and ending Sunday. She obtained the information for Saturday–Sunday digital camera sales at the various outlets and paired it with the number of times the advertisement was shown on the local TV stations. The purpose is to find whether there is any relationship between the number of times the advertisement was aired and digital camera sales. The pairings are:

Location of

Number of

Saturday–Sunday Sales

TV Station

Airings

(\$ thousands)

Providence

4

15

Springfield

2

8

New Haven

5

21

Boston

6

24

Hartford

3

17

a.

What is the dependent variable?

is the dependent variable.

c.

Coefficient of correlation

d.

Interpret these statistical measures.

The statistical measures obtained here indicate

correlation between the variables.

4.
value:
10.00 points

The owner of Maumee Ford-Mercury-Volvo wants to study the relationship between the age of a car and its selling price. Listed below is a random sample of 12 used cars sold at the dealership during the last year.

Car

Age (years)

Selling Price (\$000)

Car

Age (years)

Selling Price (\$000)

1

9

8.1

7

8

7.6

2

7

6.0

8

11

8.0

3

11

3.6

9

10

8.0

4

12

4.0

10

12

6.0

5

8

5.0

11

6

8.6

6

7

10.0

12

6

8.0

a.

If we want to estimate selling price on the basis of the age of the car, which variable is the dependent variable and which is the independent variable?

is the independent variable and

is the dependent variable.

b-1.

Determine the correlation coefficient. (Negative amounts should be indicated by a minus sign. Round your answers to 3 decimal places.)

X

Y

( )2

( )2

( )( )

9.0

8.1

1.192

0.007

1.420

0.099

7.0

6.0

-0.908

3.674

0.825

1.741

11.0

3.6

2.083

4.340

10.945

-6.892

12.0

4.0

3.083

9.507

8.458

-8.967

8.0

5.0

-0.917

-1.908

3.642

1.749

7.0

10.0

-1.917

3.092

9.558

-5.926

8.0

7.6

-0.917

0.692

0.840

-0.634

11.0

8.0

2.083

1.092

4.340

2.274

10.0

8.0

1.083

1.092

1.174

1.192

12.0

6.0

3.083

-0.908

9.507

0.825

6.0

8.6

-2.917

1.692

8.507

2.862

-4.934

6.0

8.0

-2.917

1.092

8.507

1.192

-3.184

107.000

82.900

=

=

sx

=

sy

=

r

=

b-2.

Determine the coefficient of determination. (Round your answer to 3 decimal places.)

c.

Interpret the correlation coefficient. Does it surprise you that the correlation coefficient is negative? (Round your answer to nearest whole number.)

correlation between age of car and selling price. So,  % of the variation in the selling price is explained by the variation in the age of the car.

5.
value:
10.00 points

Pennsylvania Refining Company is studying the relationship between the pump price of gasoline and the number of gallons sold. For a sample of 20 stations last Tuesday, the correlation was .78.

At the .01 significance level, is the correlation in the population greater than zero? (Round your answer to 3 decimal places.)

The test statistic is .

Decision:

H0: ρ ≤ 0

QNT 351 Week 4 LT Assignment
1.     The following hypotheses are given.
H0: π = .40
H1: π ≠ .40
A sample of 120 observations revealed that p = .30. At the .05 significance level, can the null hypothesis be rejected?
1.     State the decision rule.
2.     Compute the value of the test statistic.
3.     What is your decision regarding the null hypothesis?
For the following Problems, use the 6 step hypothesis testing
2.     The manufacturer of the X-15 steel-belted radial truck tire claims that the mean mileage the tire can be driven before the tread wears out is 60,000 miles. Assume the mileage wear follows the normal distribution and the standard deviation of the distribution is 5,000 miles. Crosset Truck Company bought 48 tires and found that the mean mileage for its trucks is 59,500 miles. Is Crosset’s experience different from that claimed by the manufacturer at the .05 significance level?
3.     The waiting time for customers at MacBurger Restaurants follows a normal distribution with a population standard deviation of 1 minute. At the Warren Road MacBurger, the quality-assurance department sampled 50 customers and found that the mean waiting time was 2.75 minutes. At the .05 significance level, can we conclude that the mean waiting time is less than 3 minutes?

4.     The null and alternate hypotheses are:
H0: π1 = π2
H1: π1 ≠ π2
A sample of 200 observations from the first population indicated that x1 is 170. A sample of 150 observations from the second population revealed x2 to be 110. Use the .05 significance level to test the hypothesis.
1.     State the decision rule.
2.     Compute the pooled proportion.
3.     Compute the value of the test statistic.
4.     What is your decision regarding the null hypothesis?

5.     The null and alternate hypotheses are:
H0: μ1 = μ2
H1: μ1 ≠ μ2
A random sample of 10 observations from one population revealed a sample mean of 23 and a sample standard deviation of 4. A random sample of 8 observations from another population revealed a sample mean of 26 and a sample standard deviation of 5. At the .05 significance level, is there a difference between the population means?

QNT 351 Week 5 LT Assignment
QNT 351: Learning Teams Problem Sets
IMPORTANT:
Showing your work and how you reached the answer is critical in receiving your grade...simply putting down values as the final answer will not earn you any points.
Week 5 LT Assignments

1.    The city council of Pine Bluffs is considering increasing the number of police in an effort to reduce crime. Before making a final decision, the council asked the chief of police to survey other cities of similar size to determine the relationship between the number of police and the number of crimes reported. The chief gathered the following sample information.

a. Which variable is the dependent variable and which is the independent variable? Hint: Which of the following makes better sense: Cities with more police have fewer crimes, or cities with fewer crimes have more police? Explain your choice.
b. Draw a scatter diagram.
c. Determine the correlation coefficient.
d. Interpret the correlation coefficient. Does it surprise you that the correlation coefficient is negative?
2. Pennsylvania Refining Company is studying the relationship between the pump price of gasoline and the number of gallons sold. For a sample of 20 stations last Tuesday, the correlation was .78. At the .01 significance level, is the correlation in the population greater than zero?

3. A study of 20 worldwide financial institutions showed the correlation between their assets and pretax profit to be .86. At the .05 significance level, can we conclude that there is positive correlation in the population?
4. The following sample observations were randomly selected.

Determine the correlation coefficient and interpret the relationship between x and y.
5. Refer to the following table

Determine the correlation coefficient and interpret the relationship between x and y.

QNT 351 Week 5 Final Exam (The 2016 Latest Version 100% Score)
QNT 351 Week 5 Final Exam
https://uopcourses.com/sd_product/qnt-351-week-5-final-exam/
Number of Questions:30 questions Time Limit:3 hours
Results: 30/30 (100%)
Q1
The Director of Golf for a local course wants to study the number of rounds played by members on weekdays. He gathered the sample information shown below for 520 rounds. At the .05 significance level, is there a difference in the number of rounds played by day of the week?
Day Rounds
Monday 124
Tuesday 74
Wednesday 104
Thursday 98
Friday 120

No, because χ2 = 7.715

Yes, because χ2 = 12.288

No, because χ2 = 11.793

Yes, because χ2 = 15.308
2
An auditor for American Health Insurance reports that 20% of policyholders submit a claim during the year. 15 policyholders are selected randomly. What is the probability that at least 3 of them submitted a claim the previous year?

.250

.200

.602

.708
3
When a class interval is expressed as 100 up to 200, _________________________.

The class interval is 99

Observations with values of 200 are included in the class

Observations with values of 200 are excluded from the class

Observations with values of 100 are excluded from the class
4
A coffee manufacturer is interested in whether the mean daily consumption of regular-coffee drinkers is less than that of decaffeinated-coffee drinkers. A random sample of 50 regular-coffee drinkers showed a mean of 4.35 cups per day, with a standard deviation of 1.2 cups per day. A sample of 40 decaffeinated coffee drinkers showed a mean of 5.84 cups per day, with a standard deviation of 1.36 cups per day. What is your computed z-statistic?

z = – 3.90

z = -5.44

z = -1.81

z = -2.45
5
You perform a hypothesis test at the .05 level of significance. Your computed p-value turns out to .042. What is your decision about the hypothesis?

You can’t render a decision unless you know the computed test statistic

You would reject Ho

You would accept Ho if it is a two-tailed test, but reject Ho if a one-tailed test

You would accept Ho
6
In a distribution, the second quartile corresponds with the __________.

Variance

Mode

Mean

Median
7
The MacBurger restaurant chain claims that the waiting time of customers for service is normally distributed, with a mean of 3 minutes and a standard deviation of 1 minute. The quality-assurance department found in a sample of 50 customers at the Warren Road MacBurger that the mean waiting time was 2.75 minutes. When you perform a test of hypothesis, what would be the resulting p-value?

.0471

.0512

.0384

.0586
8
The first card selected from a standard 52-card deck was a king. If it is returned to the deck, what is the probability that a king will be drawn on the second selection?

1/4 or 0.25

1/3 or 0.33

1/13 or 0.077

12/13 or 0.923
9
An example of a qualitative variable is _________________.

Color of ink in a pen

Number of children in a family

Miles between oil changes

Weight of a person
10
When statisticians analyze sample data in order to draw conclusions about the characteristics of a population, this is referred to as:

Descriptive statistics

Data analysis

Data summarization

Statistical inference
11
The ages of all the patients in the isolation ward of the hospital are 38, 26, 13, 41, and 22. What is the population standard deviation?

9.26

6.92

10.33

15.85
12
Consider the following regression analysis between sales (Y in \$1,000) and social media advertising (X in dollars).
= 55,000 + 7X
The regression equation implies that an:

increase of \$1 in advertising is associated with an increase of \$7,000 in sales.

increase of \$1 in advertising is associated with an increase of \$62,000 in sales.

increase of \$7 in advertising is associated with an increase of \$7,000 in sales.

increase of \$1 in advertising is associated with an increase of \$7 in sales.
13
The tread life of tires mounted on light-duty trucks follows the normal probability distribution with a mean of 60,000 miles and a standard deviation of 4,000 miles. Suppose you bought a set of four tires, what is the likelihood the mean tire life of these four tires is between 57,000 and 63,000 miles?

1.00

0.8664

0.4332

Very likely
14
University officials say that at least 70% of the voting student population supports a fee increase. If the 95% confidence interval estimating the proportion of students supporting the fee increase is [0.75, 0.85], what conclusion can be drawn?

Seventy percent is not in the interval, so assume it will not be supported.

The interval estimate is above 70%, so infer that it will be supported.

Seventy percent is not in the interval, so another sample is needed.

Since this was not based on the population, no conclusion can be drawn.
15
A study by the National Park Service revealed that 50% of the vacationers going to the Rocky Mountain region visit Yellowstone Park, 40% visit the Grand Tetons, and 35% visit both. What is the probability that a vacationer will visit at least one of these magnificent attractions?

0.05

0.95

0.55

0.35
16
The distribution of a sample of the outside diameters of PVC pipes approximates a symmetrical, bell-shaped distribution. The arithmetic mean is 14.0 inches, and the standard deviation is 0.1 inches. About 68% of the outside diameters lie between what two amounts?

13.9 and 14.1 inches

13.0 and 15.0 inches

13.8 and 14.2 inches

13.5 and 14.5 inches
17
A group of women tried five brands of fingernail polish and ranked them according to preference. What level of measurement is this?

Nominal

Ordinal

Ratio

Interval
18
What is the range of values for a coefficient of correlation?

0 to +1.0

Unlimited range

-1.0 to +1.0 inclusive

-3 to +3 inclusive
19
Which approach to probability assumes that the events are equally likely?

Mutually exclusive

Empirical

Subjective

Classical
20
What is the median of 26, 30, 24, 32, 32, 31, 27, and 29?

30

29.5

29

32
21
Sales at a fast-food restaurant average \$6,000 per day. The restaurant decided to introduce an advertising campaign to increase daily sales. To determine the effectiveness of the advertising campaign, a sample of 49 days of sales was taken. It found that the average daily sales were \$6,400 per day. From past history, the restaurant knew that its population standard deviation is about \$1,000. The value of the test statistic is _______.

1.96

6,400

6,000

2.8
22
The mean of a normal distribution is 400 pounds. The standard deviation is 10 pounds. What is the probability of a weight between 415 pounds and the mean of 400 pounds?

0.1932

0.3413

0.4332

0.5000
23
Which of the following is true regarding the normal distribution?

The mean, median, and mode are all equal.

It has two modes.

The points of the curve meet the x-axis at z = -3 and z = 3.

It is asymmetrical.
24
A time series trend equation for Hammer Hardware is Y’ = 5.6 + 1.2t, where sales are in millions of dollars and t increases by one unit for each year. If the value of sales in the base year of 2016 is \$5.6 million, what would be the estimated sales amount for 2018?

\$6.8 million

Unable to determine from given information

\$5.6 million

\$8 million
25
A research firm conducted a survey to determine the mean amount steady smokers spend on cigarettes during a week. A sample of 64 smokers revealed that  = \$20 and S = \$5. What is the 95% confidence interval for μ?

\$18.78 to \$21.23

\$18.60 to \$21.40

18.37 to 21.63

18.16 to 21.84
26
A weight-loss company wants to statistically prove that its methods work. They randomly selected 10 clients who had been on the weight loss program for between 55 and 65 days. They looked at their beginning weights and their current weight. The statistical test they should utilize is:

t test for difference in paired samples

z test for two population means

z test for two population proportions

t test for two population means
27
As the size of the sample increases, what happens to the shape of the distribution of sample means?

It approaches a normal distribution.

It cannot be predicted in advance.

It is negatively skewed.

It is positively skewed.
28
Each month the National Association of Purchasing Managers publishes the NAPM index. One of the questions asked on the survey to purchasing agents is: Do you think that the economy is expanding? Last month, of the 300 responses, 160 answered “yes” to the question. This month, 170 of the 290 responses indicated that the economy is expanding. If you’re testing to find if a larger proportion of agents believe that the economy is expanding this month, what is your computed test statistic?

t = -1.07

z = -1.29

t = -1.25

z = -1.11
29
A group of 100 students was surveyed about their interest in a new International Studies program. Interest was measured in terms of high, medium, or low. In the study, 30 students responded high interest, 40 students responded medium interest, and 30 students responded low interest. What is the relative frequency of students with high interest?

.030

.40

.30

.50
30
A hypothesis regarding the weight of newborn infants at a community hospital is that the mean is 6.6 pounds. A sample of seven infants is randomly selected and their weights at birth are recorded as 9.0, 7.3, 6.0, 8.8, 6.8, 8.4, and 6.6 pounds. What is the alternate hypothesis?

H1: µ 7.6

H1: µ ≠ 6.6

H1: µ ≥ 6.6

H1: µ = 6.6