Question 9.48

Children in the United States account directly for

$36 billion in sales annually. When their indirect influence

over product decisions from stereos to vacations is considered,

the total economic spending affected by children in the

United States is $290 billion. It is estimated that by age 10.

a child makes an average of more than five trips a week to a

store (data extracted from M. E. Goldberg, G. 1. Gorn, L. A.

Peracchio, and G. Bamossy, “Understanding Materialism

Among Youth,” Journal of ConSlimer Psychology, 2003.

13(3), pp. 278-288). Suppose that you want to prove that

children in your city average more than five trips a week to

a store. Let fL represent the population mean number of

times children in your city make trips to a store.

a. State the null and alternative hypotheses.

b. Explain the meaning of the Type I and Type II errors in

the context of this scenario.

c. Suppose that you carry out a similar study in the city in

which you live. You take a sample of ) 00 children and find that the mean number of trips to the store is 5.47 and the sample SD of the number of trips to store is 1.6. At the 0.01 level of significance, is there evidence that the population mean number of trips to the store is greater than 5 per week?

d) Interpret the meaning of the p- value in (c )