Question: A large corporation has been sending many of its first-level managers to an off-site supervisory skills course. Four different management development centers offer this course, and the corporation wants to determine whether they differ in the quality of training provided. A sample of 20 employees who have attended these programs has been chosen and the employees ranked in terms of supervisory skills. The results follow.

Note that the top-ranked supervisor attended course 2 and the lowest-ranked supervisor attended course 4. Use α = .05 and test to see whether there is a significant difference in the training provided by the four programs.