People procrastinate when it comes to an unpleasant chore, but consumers often put off a good experience, too. Marketing researchers gave out coupons for either one or two free movie tickets to 120 students. Sixty coupons expired within a month, and 60 expired within 3 months. Students were randomized to have 4 samples of 30 for each combination of 1 or 2 tickets and 1 month or 3 months to expiration. At the end of 3 months, theatres reported which coupons had been used.17
(a) Which group used the most tickets? The least?
(b) Are these samples large enough to use for two-sample comparison?
(c) Assuming the samples are large enough to satisfy the necessary conditions, ft and interpret the regression of use on the assigned group.
(d) Are any of the differences among the four groups statistically significant?
(e) Interpret the results of this analysis for retailers using coupons.