A researcher conducts an experiment to determine whether moderate doses of St. Johns Wort have any effect of memory for college students. For this study, what is the independent variable?

Question

a.
Cannot answer without more information.

b.
The group of college students.

c.
The memory score for each participant.

d.
The amount of St. Johns Wort given to each participant.

Answer 1

The correct answer is:

d. The amount of St. Johns Wort given to each participant.

In this experiment, the independent variable is the one that is manipulated by the researcher to observe its effect on the dependent variable. Here, the amount of St. Johns Wort is being varied to see if it has an effect on memory scores.