During childhood, the odds of dying in an accident are about three times greater than the odds of dying due to cancer

Echolalia is a disorder in which sufferers ______

a. hear every sound multiple times as if each sound were accompanied by a repetitive echo b. stutter repeatedly when they get nervous or anxious c. imitate the physical gestures of other people around them d. repeat words that are said to them

In a carefully controlled experiment, the only possible cause for any effect noted in the dependent variable is the

a. independent variable. b. extraneous variable. c. random assignment. d. random selection.