Question: The president of a large company is in the process of deciding whether to adopt a lunch-time exercise program. The purpose of such programs is to improve the health of workers and, in so doing, reduce medical expenses. To get more information, he instituted an exercise program for the employees in one office. The president knows that during the winter months medical expenses are relatively high because of the incidence of colds and flu. Consequently, he decides to use a matched pairs design by recording medical expenses for the 12 months before the program and for 12 months after the program. The "before" and "after" expenses (in thousands of dollars) are compared on a month-to-month basis. Use the following Excel output to test the claim that the exercise programs reduce medical expenses, at 5% level of significance.
| Month |
Before Program |
After Program |
| Jan |
68 |
59 |
| Feb |
44 |
42 |
| Mar |
30 |
20 |
| Apr |
58 |
62 |
| May |
35 |
25 |
| Jun |
33 |
30 |
| Jul |
52 |
56 |
| Aug |
69 |
62 |
| Sep |
23 |
25 |
| Oct |
69 |
75 |
| Nov |
48 |
40 |
| Dec |
30 |
46 |