Do Pinterest shoppers and Facebook shoppers differ with respect to spending behavior? A study of browser based shopping sessions reported that Pinterest shoppers spent a mean of $ 153 per order and Facebook shoppers spent a mean of $ 85 per order. (Data extracted from bit. ly/ 14wG1YI.) Suppose that the study consisted of 500 Pinterest shoppers and 500 Facebook shoppers, and the standard deviation of the order value was $ 150 for Pinterest shoppers and $ 80 for Facebook shoppers. Assume a level of significance of 0.05.

a. Is there evidence of a difference in the variances of the order values between Pinterest shoppers and Facebook shoppers?

b. Is there evidence of a difference in the mean order value between Pinterest shoppers and Facebook shoppers?

c. Construct a 95% confidence interval estimate for the difference in mean order value between Pinterest shoppers and Facebook shoppers.