Question: In a study of the sleep inducing effect of 5 medications A, B, C, D, E a physician administered a standard dose of each to 6 different subjects, 30 in all. He then measured how much time elapsed before the subjects went to sleep. Prior to doing the experiment he was merely curious as to whether there was much variation in the effect produced by the drugs. The data are summarized in the following analysis or variance.

SOURCE SS DF MS F

Between Chemicals 2000 4 500 10

Within Chemicals 1250 25 50

The mean numbers of minutes until going to sleep were

Drug A B C D E

Mean 19 64 66 67 71

Upon examining the above means answer the following questions.

a. Is the gap between medication B and medication E significant? Give an approximate p value.

b. Perform a statistical procedure to compare the means of the 5 groups and give a p value.