A consumer goods manufacturer recently conducted an experiment in which coupon formats were tested in different variations, classified as “high,” “moderate,” or “low” value. The face values of the high-, medium-, and low-value cents-off coupon treatments were 75 cents, 50 cents, and 25 cents, respectively. Similarly, “buy one get one free,” “buy two get one free,” and “buy three get one free”

treatments were classified as high-, moderate-, and low-value treatment conditions for the second coupon type. Redemption rates for each coupon treatment are shown in the table below:

COUPON REDEMPTION RATE Type of Coupon High Value Moderate Value Low Value Cents-off 1.5% 2% 1.5%
Buy X, Get One Free 4% 2% 0.5%

Do the results shown in this table provide evidence of concomitant variation? Why or why not? Interpret these results. What conclusions can be drawn regarding the relationship between the type of coupon and the coupon redemption rate in this experiment? What other factors should be considered when interpreting the data?