=+78. Employee athletes, part 2. A small company, on hearing about the employee athlete program (see Exercise 77) at the large company down the street, decides to try it as well.

To measure the difference in productivity, they measure the average number of keystrokes per hour of 23 employees before and after the program is instituted. The data follow:

Keystrokes per Hour Before After Difference

(After − Before)

Mean 1497.3 1544.8 47.5 SD 155.4 136.7 122.8 N 23 23 23