Chapter 8, Problem 20CQ

For Exercises 1 through 25, perform each of the following steps.

a. State the hypotheses and identify the claim.

b. Find the critical value(s).

c. Compute the test value.

d. Make the decision.

e. Summarize the results.

Use diagrams to show the critical region (or regions), and use the traditional method of hypothesis testing unless otherwise specified.

20. Experience of Taxi Drivers A taxi company claims that its drivers have an average of at least 12.4 years’ experience. In a study of 15 randomly selected taxi drivers, the average experience was 11.2 years. The standard deviation was 2. At α = 0.10, is the number of years’ experience of the taxi drivers really less than the taxi company claimed?