Suppose It Is Desired to Estimate the Average Time a Customer

Multiple Choice

Suppose it is desired to estimate the average time a customer spends in a particular store to within 5 minutes (e.g., + 5 minutes) at 97% reliability. It is estimated that the standard deviation of the times is 15 minutes. How large a sample should be taken to get the desired interval?

A) n = 6.51
B) n = 150
C) n = 43
D) n = 7