Question: A medical research firm performed an investigational study of the impact on lowering cholesterol levels by a combined regimen of different five diet plans and four exercise programs. The data from 20 participants was as follows, with the cell entries representing the drop in measured cholesterol levels:

At the 5% level of significance, determine whether (a) the five diet plans lower cholesterol levels comparably, and (b) the four exercise programs lower cholesterol comparably. [COMMENTS & HINTS: Think two-way ANOVA!]