# QNT 275 Week 5 Quiz

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QNT 275 Week 5 Quiz

Chapter 08, Section 8.2, Problem 010

Correct.

Find  z for a  90% confidence level.

Round your answer to two decimal places.

z=

the tolerance is +/-2%

Chapter 08, Section 8.2, Problem 011

For a data set obtained from a sample, n=80 and x¯=46.55. It is known that σ=3.9.

a. What is the point estimate of μ?

The point estimate is   .

b. Make a 97% confidence interval for μ.

Round your answers to two decimal places.

(  ,  )

c. What is the margin of error of estimate for part b?

Round your answer to three decimal places.

E=

Chapter 08, Section 8.2, Problem 017a

Correct.

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

E=2.4, σ=12.35, confidence level=99%.

Round your answer to the nearest integer.

n=

the tolerance is +/-2%

Chapter 08, Section 8.3, Problem 034b

Correct.

For the following, find the area in the appropriate tail of the t distribution.

t=1.711 and n=25.

Round your answer to 3 decimal places.

Area in the

tail is

the tolerance is +/-2%

Chapter 09, Section 9.1, Problem 004a

Correct.

Which of the following is a left-tailed test?

H0: μ=101, H1: μ<101

H0: μ=48, H1: μ≠48

H0: μ=73, H1: μ73

Chapter 09, Section 9.1, Problem 007

Correct.

Write the null and alternative hypotheses for the following example. Determine if the example is a case of a two-tailed, a left-tailed, or a right-tailed test.

To test if the mean length of experience of airport security guards is different from 3 years.

≠H0: μ≠3 years, H1: μ=3 years, right-tailed test

H0: μ=3 years, ≠H1: μ≠3 years, two-tailed test

H0: μ=3 years, H1: μ<3 years, left-tailed test

H0: μ=3 years, H1: μ3 years, right-tailed test

≤H0: μ≤3 years, H1: μ3 years, two-tailed test

Chapter 09, Section 9.2, Problem 014c

Correct.

Consider H0: μ=38 versus H1: μ38. A random sample of 35 observations taken from this population produced a sample mean of 40.26. The population is normally distributed with σ=7.2.

Calculate the p-value. Round your answer to four decimal places.

p=

the tolerance is +/-2%

Chapter 09, Section 9.2, Problem 020a

Correct.

A random sample of 125 observations produced a sample mean of 31. Find the critical and observed values of z for the following test of hypothesis using α=0.01. The population standard deviation is known to be 5 and the population distribution is normal.

H0: μ=28 versus H1: μ≠28.

Round your answers to two decimal places.

zcritical left =

zcritical right =

zobserved =

Chapter 09, Section 9.2, Problem 025b

Correct.

The manufacturer of a certain brand of auto batteries claims that the mean life of these batteries is 45 months. A consumer protection agency that wants to check this claim took a random sample of 24 such batteries and found that the mean life for this sample is 43.05 months. The lives of all such batteries have a normal distribution with the population standard deviation of 4.5 months.

Test the hypothesis H0: μ=45 months versus H1: μ<45 months using the critical-value approach and α=0.1.

H0 is

Chapter 01, Section 1.3, Video Quiz 2

Please view the following video before answering this question. Soda with Callouts

The number of sodas is what type of data?

Discrete.

Continuous.