1. The management LL Bean believes that women over 50 years old spend more per year than women under 50 years of age. To test this you access their sales records and select a fair number of random samples of yearly sales transactions. Specifically you find that:

150 women over 50 spent an average of $500 last year with a variance of $5,600 and 250 women under 50 spent an average of $480 last year with a variance $6,400.

A. Calculate a 95% confidence interval on the difference between the over 50 and under 50 year old mean sales for last year. Interpret this confidence interval.