1. The worksheet Sales Data.xls provides data on a sample of customers. An industry trade publication stated that the average profit per customer for this industry was $4500. Can this company claim that they are meeting the industry standard?
2. The managing partner of a major consulting firm is trying to assess the effectiveness of expensive computer skills training given to all new entry-level professionals. In an effort to make such an assessment, she administers a computer skills test immediately before and after the training program to each of 40 randomly selected employees. The pre-training and post-training scores are recorded in the file computer skills training.xls. using a 5% level of significance, do the sample data support the claim that the organization's training program is increasing the new employee's working knowledge of computing?
3. A marketing study found that the mean spending in 15 categories of consumer items for 297 respondents in the 18-34 age group was $71.86 with a standard deviation of $70.90. For 736 respondents in the 35+ age group, the mean and standard deviation were $61.53 and $45.29, respectively. Test the hypothesis that there is no difference in the mean spending between these two groups.
4. The file ElectronicExpress.xls contains data on 400 orders placed to the ElecExpress Company over the period of several months. For each order, the file lists the time of day, the type of credit card used, the region of the country where the customer resides, and others. Use a chi-square test for independence to see whether the following variables are independent of one another. If the variables appear to be related discuss the form of dependence you see.
a) Time and Region
b) Region and BuyCategory
c) Gender and CarType
2. Researchers aren't sure of the exact mechanism, but there is evidence in the literature that exercise and cholesterol are related. A large firm, interested in lowering the health care insurance costs of its employees, wonders if encouraging an exercise program would lower levels of cholesterol for its employees, making employees healthier overall. The firm takes a sample of employees and administers a test that measures emotional stress by asking questions about current life issues of the employee. The answers to these questions allows for the categorization of employees into "low" or "high" levels of stress. As part of the series of questions, the test also asks if employees are active in an exercise program (to which employees answered "yes" or "no"). Using only the data in the file cholesterol and stress.xls (that is, there is no need to do any internet research for this question), is there any evidence that the firm can lower average cholesterol levels for its employees by encouraging the participation of exercise programs?