As part of a study to determine the effects of allowing the use of credit cards for alcohol purchases in Canada (“Changes in Alcohol Consumption Patterns Following the Introduction of Credit Cards in Ontario Liquor Stores,” Journal of Studies on Alcohol [1999]: 378–382), randomly selected individuals were given a questionnaire asking them how many drinks they had consumed during the previous week. A year later (after liquor stores started accepting credit cards for purchases), these same individuals were again asked how many drinks they had consumed in the previous week. The values in the accompanying table are consistent with summary values presented in the article.
- a. The standard deviations of the differences were quite large. Explain how this could be the case.
- b. Calculate a 95% confidence interval for the mean difference in drink consumption for credit-card shoppers between 1994 and 1995. Is there evidence that the mean number of drinks decreased?
- c. Test the hypothesis that there was no change in the mean number of drinks between 1994 and 1995 for the non-credit-card shoppers. Be sure to calculate and interpret the P-value for this test.
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Chapter 11 Solutions
Introduction to Statistics and Data Analysis
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- 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 furnishings, apparel, and entertainment (U.S. 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 card charges for dining out (population 2). Using the difference data, the sample means difference was = $838, and the sample standard deviation was sd = $1,204. Formulate the null and alternative hypotheses to test for no difference between the population mean credit card charges for groceries and the population mean credit card charges for dining out.H0: d Selectgreater than or equal to 0greater than 0less than or equal to 0less than 0equal to 0not equal to 0Item 1Ha: d Selectgreater than or equal to 0greater than 0less than or…arrow_forwardBank 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 furnishings, apparel, and entertainment (U.S. 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 card charges for dining out (population 2). Using the difference data, the sample mean difference was = $836, and the sample standard deviation was sd = $1,106. Formulate the null and alternative hypotheses to test for no difference between the population mean credit card charges for groceries and the population mean credit card charges for dining out.H0: d Ha: d Use a .05 level of significance. What is the p-value?The p-value is Can you conclude that the population means differ? Which category, groceries or dining out, has a…arrow_forwardBank 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 furnishings, apparel, and entertainment (U.S. 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 card charges for dining out (population 2). Using the difference data, the sample mean difference d - = $813, and the sample standard deviation was sa = $1,121. a. Formulate the null and alternative hypotheses to test for no difference between the population mean credit card charges for groceries and the population mean credit card charges for dining out. Họ: 4 a Select Ha: 4d Select was b. Use a .05 level of significance. What is the p-value? The p-value is Select Can you conclude that the population means differ? Select c. Which…arrow_forward
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