Question: A company that produces and markets videotaped continuing education programs for the financial industry has traditionally mailed sample tapes that contain previews of the programs to prospective customers. Customers then agree to purchase the program tapes or return the sample tapes. A group of sales representatives studied how to increase sales and found that many prospective customers believed it was difficult to tell from a sample tape alone whether the educational programs would meet their needs. The sales representatives performed an experiment to test whether sending the complete program tapes for review by customers would increase sales. They selected 80 customers from the mailing list and randomly assigned 40 t receive the sample tapes and 40 to receive the full-program tapes for review. They then determined the number of tapes that were purchased and returned in each group. The results of the experiment are as follows:

a. At the 0.05 level of significance, is there evidence of a difference in the proportion of tapes purchased on the basis of the type of tape sent to the customer?

b. On the basis of the results of ( a ), which tape do you think a representative should send in the future? Explain the rationale for your decision.

The sales representatives also wanted to determine which of three initial sales approaches result in the most sales: ( 1 ) a video sales-information tape mailed to prospective customers, ( 2 ) a personal sales call to prospective customers, and (3 ) a telephone call to prospective customers.

A random sample of 300 prospective customers was selected, and 100 were randomly assigned to each of the three sales approaches. The results, in terms of purchases of the full-program tapes, are as follows:

c. At the 0.05 level of significance, is there evidence of a difference in the proportion of tapes purchased on the basis of the sales strategy used?

d. If appropriate, use the Marascuilo procedure and a=0.05 to determine which sales approach are different.

e. On the basis of the results of ( c ) and ( d ), which sales approach do you think a representative should use in the future? Explain the rationale for your decision.