A Major Retail Clothing Store Is Interested in Estimating the Difference

Multiple Choice

A major retail clothing store is interested in estimating the difference in mean monthly purchases by customers who use the store's in-house credit card versus using a Visa, Mastercard, or one of the other major credit cards. To do this, it has randomly selected a sample of customers who have made one or more purchases with each of the types of credit cards. The following represents the results of the sampling: Given this information, which of the following statements is true?

A) If either of the sample sizes is increased, the resulting confidence interval will have a smaller margin of error.
B) If the confidence level were changed from 95 percent to 90 percent, the margin of error in the estimate would be reduced.
C) Neither A nor B are true.
D) Both A and B are true.