For the data in problem 9,

a. Compute SStotal and SS between treatments.

b. Eliminate the mean differences between treatments by adding 2 points to each score in treatment I, adding 1 point to each score in treatment II, and subtracting 3 points from each score in treatment III. (All three treatments should end up with M = 3 and T = 15.)

c. Calculate SStotal for the modified scores. (Caution: You first must find the new value for ΣX2.)

d. Because the treatment effects were eliminated in part b, you should find that SStotal for the modified scores is smaller than SStotal for the original scores. The difference between the two SS values should be exactly equal to the value of SS between treatments for the original scores.