Therefore, the researcher recruited 72 participants split evenly between males and females. Males and females were further (equally) subdivided into whether they were at low or high risk of heart attack. Each of these subgroups then received one of the three different drugs. After one month on the different drugs, cholesterol concentration was measured. The researcher wants to understand how each factor (i.e., type of drug, risk of heart attack, gender) interact to predict cholesterol concentration.