question archive 1) 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
1) 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
Subject:StatisticsPrice: Bought3
1) 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. Using data from a sample of 17 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 $861, and the sample variance of the difference was $2,788,900.
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.
b. Use a 0.05 level of significance. Can you conclude that the population means differ? What is the p?value?
c. Which category, groceries or dining out, has a 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?
2). Most individuals are aware that the average annual repair cost for an automobile depends on the age of the automobile. A researcher is interested in finding out whether the variance of the annual repair costs also increases with the age of the automobile. A sample of 29 automobiles that were four years old showed a sample standard deviation for annual repair costs of $270 and a sample of 26 automobiles that were two years old showed a sample standard deviation for annual repair costs of $230.
a. State the null and alternative versions of the research hypothesis that the variance in annual repair costs is larger for the older automobiles.
b. At a 0.01 level of significance, what is your conclusion? What is the pvalue? Discuss the reasonableness of your findings.
3).
The National Association of Home Builders provided data on the cost of the most popular home remodeling projects. Sample data on cost in thousands of dollars for two types of remodeling projects are as follows.
|
kitchen |
Master bedroom |
|
25.2 |
18 |
|
17.4 |
22.9 |
|
22.8 |
26.4 |
|
21.9 |
24.8 |
|
19.7 |
26.9 |
|
|
17.8 |
|
23 |
24.6 |
|
19.7 |
21 |
|
16.9 |
|
|
21.8 |
|
|
23.6 |
|
a) Develop a point estimate of the difference between the population mean remodeling costs for the two types of projects.
b. Develop a 90% confidence interval for the difference between the two population means.
