Chapter 8.3, Problem 19E

For Exercises 7 through 23, perform each of the following steps.

a. State the hypotheses and identify the claim.

b. Find the critical value(s).

c. Find the test value.

d. Make the decision.

e. Summarize the results.

Use the traditional method of hypothesis testing unless otherwise specified.

19. Commute Time to Work A survey of 15 large U.S. cities finds that the average commute time one way is 25.4 minutes. A chamber of commerce executive feels that the commute in his city is less and wants to publicize this. He randomly selects 25 commuters and finds the average is 22.1 minutes with a standard deviation of 5.3 minutes. At α = 0.10, is he correct?

Source: New York Times Almanac.