Chapter 10.5, Problem 10.52E

In response to an inquiry from its national office, the manager of a local bank has stated that her bank’s average service time for a drive-through customer is93 seconds. A student intern working at the bank happens to be taking a statistics course and is curious as to whether the true average might be some value other than 93 seconds. The intern observes a simple random sample
of 50 drive-through customers whose average service time is 89.5 seconds, with a standard deviation of 11.3 seconds. From these sample results, and using the 0.05 level of significance, what conclusion would the student reach with regard to the bank manager’s claim?