A psychiatrist studied the effects of three antidepressants on subjects in three different age groups. Each subject was rated on a scale of 0 to 100, with higher numbers indicating greater relief from depression. The following table presents the results.

a. Compute the nine cell means.

b. Construct an interaction plot. Do there seem to be strong interactions?

c. Use technology to perform a test for interactions. Do you reject the hypothesis of no interactions? Are the results of the test consistent with the interaction plot?

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18-30 Drug A Drug B 52 51 51 50 Drug C 71 72 70 71 43 43 41 42 Age Group 31-50 53 51 53 52 62 61 60 61 81 83 82 82 51-80 57 55 58 56 65 66 66 67 86 84 87 86