30. Supervisory Skills Developed by Off-Site Training Courses. A large corporation sends many of its first-level managers to an off-site supervisory skills training course.

Four different management development centers offer this course. The director of human resources would like to know whether there is a difference among the quality of training provided at the four centers. An independent random sample of five employees was chosen from each training center. The employees were then ranked 1 to 20 in terms of supervisory skills. A rank of 1 was assigned to the employee with the best supervisory skills. The ranks are shown. Use a = .05 and test whether there is a significant difference among the quality of training provided by the four programs.

Course A B C D 3 2 19 20 14 7 16 4 10 1 9 15 12 5 18 6 13 11 17 8