In Exercise 5, we saw a regression to predict the sales per person at a movie theater in terms of the time (in minutes) before the show. The model was:
Sales = 4.3 + 0.265 Minutes.
a) A 90% prediction interval for sales to a concessions c­ustomer 10 minutes before the movie starts is ($ 4.60, $ 9.30). Explain how to interpret this interval.
b) A 90% confidence interval for the mean of sales per per-son 10 minutes before the movie starts is ($ 6.65, $ 7.25). Explain how to interpret this interval.
c) Which interval is of particular interest to the concessions manager? Which one is of particular interest to you, the moviegoer?