For the previous exercise, show a hypothetical set of population means for the four groups that would have
a. A dose effect but no drug effect.
b. A drug effect but no dose effect.
c. A drug effect and a dose effect.
d. No drug effect and no dose effect.
Previous exercise
An experiment randomly assigns 100 subjects suffering from high cholesterol to one of four groups: low-dose Lipitor, high-dose Lipitor, low-dose Zocor, high-dose Zocor. After three months of treatment, the change in cholesterol level is measured.