Chapter 12.1, Problem 16E

For Exercises 7 through 20, assume that all variables are normally distributed, that the samples are independent, that the population variances are equal, and that the samples are simple random samples, one front each of the populations. Also, for each exercise, perform the following steps.

a. State the hypotheses and identify the claim.

b. Find the critical value.

c. Compute the test value.

d. Make the decision.

e. Summarize the results, and explain where the differences in the means are.

Use the traditional method of hypothesis testing unless otherwise specified.

16. Annual Child Care Costs Annual child care costs for infants are considerably higher than for older children. At a = 0.05, can you conclude a difference in mean infant day care costs for different regions of the United States? (Annual costs per infant are given in dollars.)

New England	Midwest	Southwest
10.390	9.449	7.644
7.592	6.985	9.691
8.755	6.677	5.996
9.464	5.400	5.386
7.328	8.372

Source: www.naccrra.org (National Allocation of Child Care Resources and Referral Agencies: “Breaking the Piggy Bank”)