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.
Sample size
|
64
|
49
|
Sample mean
|
$140
|
$125
|
Population standard deviation
|
$10
|
$8
|
A point estimate for the difference between the mean purchases of the users of the two credit cards is:
A. 2
B. 18
C. 265
D. 15