an insurance company has the business objective of reducing the amount of time it takes to approve applications for life insurance. During a period of one month, you collect a random sample of 27 approved policies and the total processing time, in days.

In the past, the mean processing time was 45 days. At a = 5%, is there evidence that the mean processing time has changed from 45 days? What assumption about the population distribution is needed to conduct the t test in (a)