7,in new york state savings banks are permitted to sell a form of the life insurance called savings bank life insurance . the approval process consists ofunderwriting ,which includes a review of the application , a medical information bureau check possible requests for additional medical information and medical examsand a policy compilation stage in which the policy pages are generated and sent to the bank for delivery .the ability to deliver approved policies to customers in atimely manner is critical to the profitability of this service. during a period of one month a random sample of 27 approved policies is selected and the totalprocessing time ,in days is recorded(and stored in insurance
73 19 16 64 28 28 31 90 60 56 31 56 22 1845 48 17 17 17 91 92 63 50 51 69 16 17
a, in the past the mean processing time was 45 days. at the 0.05 level of significance is there evidence that the mean processing time has changed from 45 days?
b, what assumption about the population distribution is needed in order to conduct the t test in (a)
c, construct a boxplot or a normal probability plot to evaluate the assumption made in (b)
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