Bank of America's Consumer Spending Survey collected data on annual credit card Charges in seven different categories of expenditures: transportation groceries, dining out, household expenses home furninshings, apparel and entertainment (US Airways Attache, December 2003). Using data from a sample of 42 credit card accounts assume that each account was used to identify the annual credit card charges for groceries (population 1) and the annual credit charges for dining out (populatio 2). Using the different data, the sample mean difference was d=$850 and the sample standard of deviationwas sd=$1123.
a. Formulate null and alternative hypothesis to test for no difference between the population mean credit card charges for groceries and the population mean card charges for dining out.
b. Use a .05 level of significance. Can you conclude that the population means differ? What is the p-value?
c. Which category, groceries or dining out, was higher population mean annual credit card charge? What is the point estimate of the difference between the population means? What is the 95% confidence interval estimate of the difference between the population means?