22. CCN and ActMedia provided a television channel targeted to individuals waiting in supermarket checkout lines. The channel showed news, short features, and advertisements. The length of the program was based on the assumption that the population mean time a shopper stands in a supermarket checkout line is 8 minutes. A sample of actual waiting times will be used to test this assumption and determine whether actual mean waiting time differs from this standard.

a. Formulate the hypotheses for this application.

b. A sample of 120 shoppers showed a sample mean waiting time of 8.5 minutes. Assume a population standard deviation σ  3.2 minutes. What is the p-value?

c. At α  .05, what is your conclusion?

d. Compute a 95% confidence interval for the population mean. Does it support your conclusion?