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

Question

Quizplus · Accepted Answer

The independent variable is the one that is manipulated or changed, which in this case is the type of toothbrush (Sonicare or manual). The dependent variable is the outcome being measured, which is the number of cavities or the condition of the teeth after using the toothbrush.

Eric Wants to Verify That Automatic Toothbrushes Work Better Than