A Researcher Is Interested in Whether Color Perception Abilities Decline

Multiple Choice

A researcher is interested in whether color perception abilities decline with age. An experiment is conducted in which college students and older adults are asked to
discriminate between various color patches. The researcher finds that the college
students perform better than the older adults, but is worried that the effect is not due to age, but rather, to the types of medications that the older adults are taking. In this experiment, medication usage is:

A) a grouping variable
B) an extraneous variable
C) a confounding variable
D) a co-dependent variable