Eric Wants to Verify That Automatic Toothbrushes Work Better Than

Multiple Choice

Eric wants to verify that automatic toothbrushes work better than manual toothbrushes. To test this, he randomly assigns 25 participants to use a Sonicare toothbrush and 25 people to use a manual toothbrush. At the end of the study period he has a dentist inspect each participants' teeth. In his study, the _____ would be considered the independent variable, whereas the _____ would be considered the dependent variable.

A) type of toothbrush; number of cavities
B) manual toothbrush; automatic toothbrush
C) automatic toothbrush; manual toothbrush
D) number of cavities; type of toothbrush