In thousands of studies, correlations between IQ and achievement test scores typically fall between

Quisley's hypothesis is that listening to classical music improves intellectual performance. He randomly divides a mathematics class into two rooms. In room A, music by Mozart plays softly in the background during a lecture. In room B, the students listen to a lecture without background music. The independent variable is ____.?

a. ?whether music played during a lecture. b. ?mathematical performance. c. ?the level of mathematics taught. d. ?present only in the control group.

The best point at which to build a pause into a chain of events leading to some unwanted behavior is:

a. at the end of the chain. b. in the middle of the chain. c. at the beginning of the chain. d. it doesn't matter.