The Management of a Department Store Is Interested in Estimating

Multiple Choice

The management of a department store is interested in estimating the difference between the mean credit purchases of customers using the store's credit card versus those customers using a national major credit card.You are given the following information. $$\begin{array} { l l l } & \text { Store's Card } & \text { Major Credit Card } \\\text { Sample size } & 64 & 49 \\\text { Sample mean } & \$ 140 & \$ 125 \\\text { Population standard deviation } & \$ 10 & \$ 8\end{array}$$ A 95% confidence interval estimate for the difference between the average purchases of all customers using the two different credit cards is

A) 13.31 to 16.69.
B) 11.68 to 18.32.
C) 12.22 to 17.78.
D) 13.04 to 16.96.