A marketing researcher wants to estimate the mean amount spent ($) on a certain retail website by members of the website's premium program. A random sample of 30 members of the website's premium program who recently made a purchase on the website yielded a mean of $2100 and a standard deviation of $150. Use Excel and the table to compute the critical value needed in the problem. a. Construct a 95% confidence interval estimate for the mean spending for all shoppers who are members of the website's premium program. SHS (Round to two decimal places as needed.) b. Interpret the interval constructed in (a). Choose the correct answer below. OA. With 95% confidence, the mean spending in dollars for all shoppers who are members of the website's premium program is between the lower and upper limits of the confidence interval. OB. The sample mean spending in 95% of all samples of 30 members of the website's premium program will be between the lower and upper limits of the confidence interval. OC. There is a 95% probability that mean spending in dollars for all shoppers who are members of the website's premium program is between the lower and upper limits of the confidence interval. OD. 95% of all shoppers who are members of the website's premium program have spent an amount in dollars that is between the lower and upper limits of the confidence interval.