In Testing the Effect of Noise on Performance of a Task,Ernie

Multiple Choice

In testing the effect of noise on performance of a task,Ernie tests half of the participants in a cool,comfortable,quiet room,and the other half in a hot,noisy room.Ernie's failure to control for temperature of the room may result in a(n)

A) externally valid study.
B) internally valid study.
C) interaction.
D) confound.