Question

Find the correlation coefficient, r, of the data described below. A movie theater manager is studying the snack buying habits of his customers. He expects that when longer movies are shown, people buy more snacks. Each week he calculates the average duration of all movies being shown and the percentage of customers who buy snacks. The manager calculates the average movie duration (in minutes), x, and the percentage of the customers who bought snacks, y.

Average movie duration - Percentage of customs that bought snacks
90 7
91 17
93 9
97 16
97 34
99 27

1. 0.2
2. 0.8
3. -0.1
4. 0.7