A researcher is trying to determine the best time of day for patients to take a cholesterol medication. A sample of men who have high cholesterol is divided into six groups. One group takes the...

A researcher is trying to determine the best time of day for patients to take a cholesterol medication. A sample of men who have high cholesterol is divided into six groups. One group takes the medication every morning, a second group takes the medication at mid-day, and a third group takes the medication each night. There are also three control groups that receive a placebo instead of the real medication, one in the morning, one at mid-day, and one at night. If the results of the study show a 50-point main effect for the medication (men taking the medicine average 50 points lower cholesterol than men taking the placebo) and also show a significant interaction between medication and time of day, then what can the researcher conclude about the effect of the medication?

a. The medication lowers cholesterol by around 50 points and it does not matter what time of day it is taken.

b. Although the average effect of the medication is to lower cholesterol by 50 points, the exact effect depends on what time of day it is taken.

 c. Because there is an interaction, you cannot conclude that the medication has any effect on cholesterol.

 d. None of the other options is an appropriate conclusion.