he owners of the Westfield Mall wished to study customer shopping habits. From earlier studies, the

owners were under the impression that a typical shopper spends 0.75 hour at the mall, with a standard

deviation of 0.10 hour. Recently the mall owners added some specialty restaurants designed to keep

shoppers in the mall longer. The consulting firm, Brunner and Swanson Marketing Enterprises, was hired to

evaluate the effects of the restaurants. A sample of 45 shoppers by Brunner and Swanson revealed that the

mean time spent in the mall had increased to 0.80 hour.

a. Develop a test of hypothesis to determine if the mean time spent

in the mall changed. Use the .10

signiFcance level

b. Suppose the mean shopping time actually increased from 0.75

hour to 0.79 hours. What is the

probability of making a Type II error?

(Round your answer to 4

decimal places.)

c. When Brunner and Swanson reported the information in part (b)

to the mall owners, the owners believed

that the probability of making a Type II error was too high. How

could this probability be reduced?