A psychologist believes that music affects a person's mood. He has some participants listen to waltzes and others listen to military marches, and then measures each participant's mood with a paper-and-pencil test. What are the independent and dependent variables?

Music (independent variable) participant's mood (dependent variable)

Explanation:

An independent variable is a variable that can be changed or controlled in an experimental research while a dependent variable is a variable that depends upon independent variable and that can be tested. In this case, the type of music such as waltzes or military march is the independent variable while the participant's mood is the dependent variable. A person's mood is dependent on the type of music he listens to.