A company is planning a large telephone survey and is interested in assessing how long it will take. In a short pilot study, 40 people are contacted by telephone and are asked the specified set of questions. The times of these 40 telephone surveys have a sample mean of x- = 9.39 minutes, with a sample standard deviation of s = 1.041 minutes.
(a) Can the company safely conclude that the telephone surveys will last on average no more than 10 minutes each?
(b) Construct a 99% one-sided /-interval that provides an upper bound on the average time of each telephone call.