Consider a 2 X 2 Experiment Design in Which Both

Multiple Choice

Consider a 2 x 2 experiment design in which both study time and sleep time have been manipulated and learning has been measured. An interaction between study time and sleep time can be interpreted to mean which of the following?

A) Sleep time affects learning, controlling for study time.
B) Sleep time has no effect on learning.
C) The effect of study time on learning is different in the different levels of sleep time.
D) If the main effects are also significant, the interaction between study time and sleep time cannot be interpreted.