QUESTION 1

Let x be a random variable representing the monthly cost of joining a health club. We may assume that x has a normal distribution and that the population standard deviation is $5.20. A fitness magazine advertises that the mean monthly cost of joining a health club is $35. You work for a consumer advocacy group and are asked to test this claim. You find that a random sample of 40 health club monthly costs has a mean of $37.30. If you assume that the population mean is $35, find the standardized sample test statistic.

A. 3.157

B. 2.149

C. 2.797

D. 1.543

QUESTION 2

Let x be a random variable that represents the length of an Atlantic croaker fish. If x is normally distributed with a mean of 10 inches and a standard deviation of 2 inches, find the probability that length of the fish is between 8.4 inches and 10.2 inches.

A. 0.672

B. 0.328

C. 0.788

D. 0.212

QUESTION 3

Let x be a random variable representing the monthly cost of joining a health club. We may assume that x has a normal distribution and that the population standard deviation is $5.20. A fitness magazine advertises that the mean monthly cost of joining a health club is $35. You work for a consumer advocacy group and are asked to test this claim. You find that a random sample of 40 health club monthly costs has a mean of $37.30. If you assume that the population mean is $35, find the P-value corresponding to the hypothesis that the average monthly cost is greater than $35 (i.e. right-tail test)

A. 0.037

B. 0.025

C. 0.012

D. 0.002

QUESTION 4

Let x be a random variable that represents the length of an Atlantic croaker fish. If x is normally distributed with a mean of 10 inches and a standard deviation of 2 inches, find the length of Croaker fish at the bottom of the top 15%.

A. 7.927 inches

B. 8.234 inches

C. 11.546 inches

D. 12.073 inches

QUESTION 5

Let x be a random variable that represents the annual salary of an elementary school teacher. The mean annual salary is reported to be $50,590. Assume the standard deviation is $1800. If a random sample of 50 elementary school teachers is selected, what is the probability that the sample mean is less than $50,000?

A. 0.0102

B. 0.0312

C. 0.373

D. 0.312

QUESTION 6

A computer repair service found that a random sample of 45 repair costs had a mean cost of $659. Assume that the population standard deviation is $125. Calculate the margin of error, E, for a 95% confidence interval for the population mean µ.

A. 48.07

B. 34.92

C. 30.55

D. 36.52

QUESTION 7

A computer repair service found that a random sample of 45 repair costs had a mean cost of $659. Assume that the population standard deviation is $125. Find the 95% confidence interval for the population mean repair cost µ of all computers.

A. (612.5 , 705.5)

B. (627.5 , 690.5)

C. (622.5 , 695.5)

D. (623.5 , 694.5)

**Subject Mathematics Statistics-R Programming**