It is often useful for companies to know who their customers are and how they became customers. In a study of credit card use, a random sample of customers who applied for the credit card without being contacted by a marketing firm, and a random sample of credit card holders who were contacted by telemarketers and convinced to apply for a credit card were drawn. The total purchases made by each group in the past month were recorded, and the sample statistics are recorded below.

	Applied for Credit Card	Contacted by Telemarketers
Sample Mean	$135.93	$126.14
Sample Standard Deviation	$31.99	$26.00
Sample Size	35	35

Setting = 0.05, can we conclude from these sample statistics that there is a significant difference in average credit card expenditure between the two customer groups?

a)State an appropriate null and alternative hypothesis for this problem.

b)Identify the critical values, and sketch the rejection region.

c)Calculate the value of the test statistic.

d)On the basis of your answers to b) and c) above, do you reject the null, or fail to reject it?

e)What do your results imply about the average credit card expenditure between the two groups?