A Researcher Wants to Compare the Performance of Three Types

A researcher wants to compare the performance of three types of pain relievers in volunteers
Suffering from arthritis. Because people of different ages may suffer arthritis of varying degrees of
Severity, the subjects are split into two groups: under 60 and over 60. Subjects in each group are
Randomly assigned to take one of the medications. Twenty minutes later they rate their levels of
Pain. This experiment …

A) has two factors, medication and age.
B) has one factor (medication) blocked by age.
C) has one factor (age) blocked by medication type.
D) uses matched pairs.
E) is completely randomized.