Professor Smith studied the effect of giving either two, four, or eight pellets of reward to rats that ran a maze. He measured how fast they ran, and how many wrong turns they made. How many levels of the independent variable did he have?
A) one
B) two
C) three
D) can't tell

Question

Quizplus · Accepted Answer

The independent variable is the number of pellets of reward, and there are three levels: two, four, or eight pellets.

Professor Smith Studied the Effect of Giving Either Two, Four