# Estimation:

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.

Store's Card Major Credit Card

Sample size 64 49

Sample mean $140 $125

Population standard deviation $10 $8

a)A point estimate for the difference between the mean purchases of the users of the two credit cards is

b) At 95% confidence, the margin of error is

c) A 95% confidence interval estimate for the difference between the average purchases of the customers using the two different credit cards is

© SolutionLibrary Inc. solutionlibary.com 9836dcf9d7 https://solutionlibrary.com/statistics/hypothesis-testing/estimation-7f8g#### Solution Preview

...Sample size of sample 1= n1 = 64

Sample 2: Major Credit Card

Mean of sample 2= M2 = $125

Standard deviation of sample 2= s2 = $8

Sample size of sample 2= n2 = 49

Confidence level= 95%

Significance level=100%-Confidence level= 5% = 100%-95.%

a)A point estimate for the difference between the mean purchases of the users of the two credit cards is

Sample 1: Sample 2:

Store's Card Major Credit Card

Mean =M = $140 $125

Standard deviation =s= $10 $8

Sample size=n= 64 49

Difference of means (M1-M2)= $15.00 ...