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 point estimate for the difference between the mean purchases of all users of the two credit cards is

A) 2.
B) 18.
C) 265.
D) 15.