A Researcher Investigates Whether There Is a Relationship Between Type

Multiple Choice

A researcher investigates whether there is a relationship between type of background music being listened to and responses to a mood inventory by having 60 randomly selected participants complete the mood inventory,with 20 randomly assigned to each of three rooms.In one room classical music is played in the background,in another hard rock music,and in a third country music.The type of background music variable is a(n)

A) true independent variable.
B) quasi-independent variable.
C) dependent variable.
D) interval scale.