8.39 e-Shopping In a report of why e-shoppers aban- don their online sales transactions, Alison Stein Well- ner found that "pages took too long to load" and "site was so confusing that I couldn't find the product" were the two complaints heard most often. Based on custom- ers' responses, the average time to complete an online order form will take 4.5 minutes. Suppose that n = 50 customers responded and that the standard deviation of the time to complete an online order is 2.7 minutes.

a. Do you think that X, the time to complete the online order form, has a mound-shaped distribution? If not, what shape would you expect?

b. If the distribution of the completion times is not normal, you can still use the standard normal distri- bution to construct a confidence interval for , the mean completion time for online shoppers. Why?

c. Construct a 95% confidence interval for u, the mean completion time for online orders.