An insurance company has the business objective of reducing theamount of time it takes to approve applications for life insurance.The approval process consists of underwriting, which includes areview of the application, a medical information bureau check,possible requests for additional medical information and medicalexams, and a policy compilation stage in which policy pages aregenerated and sent for delivery. The ability to deliver thepolicies to customers in a timely manner is critical to theprofitability of the service. During a period of one month, arandom sampling of 27 approved policies is selected, and the totalprocessing time, in days, is collected. These data are stored inthe table called Insurance.

73 19 16 64 28 28 31 90 60 56 31 56 31 56 22 18 45 48 1717 17 91 92 63 50 51 69 16 17

A.         In thepast, the mean processing time was 45 days. At the 0.05 level ofsignificance, is there evidence that the mean processing time haschanged in 45 days?

B.         Whatassumption about the population distribution is needed to conductthe t-test?

C.         Construct aboxplot or a normal probability plot to evaluate the assumptionmade in (b).

D. Do you think that the assumption needed in order to conductthe t-test in(a) is valid? Explain.

Use Excel to solve part C