4. (a) In a random sample of 150 large retailers, 95 used linear regression as a method of forecasting sales. In an independent random sample of 200 small retailers, 100 used linear regression as a method of forecasting sales. i. Find a 99% confidence interval for the difference between the two population proportions. ii. What do you conclude from your confidence interval? iii. Repeat i. and ii. but for a 94% confidence interval. What is your finding?