Determine how the particular sales representative and the number of sales calls (one, three, or five) made to a doctor influence the amount (in thousands of dollars) that each doctor prescribes of a drug. Use the data in the Doctors. x15x file to determine the answers to the following problems:

a. How can the representative and number of sales calls influence the sales volume?

b. If Rep 3 makes five sales calls to a doctor, you are 95-percent sure she will generate prescriptions within what range of dollars?