Four individuals participate Each subject was placed in a stressful situation on three different occasions. Each time a different method was used to reduce the stress of the subject. The response variable is the amount of decrease in stress level measured before and after application of treatment. The results were the following: You can assume that the underlying populations are normally distributed with equal variances. Treatment
Subject A B C
1 16 26 22
2 16 20 23
3 17 21 22
4 28 29 36

Required:
Can we conclude from this data that the three methods differ in effectiveness?