A History Class of 50 Students Has Agreed to Be

Multiple Choice

A history class of 50 students has agreed to be the subject of a research study.Half of the class has been asked to study for the next history test while listening to classical music.The remaining half has been asked to study in a completely silent environment.The test scores of the two groups will be compared at the end of the experiment.In this experiment,which of the following is the dependent variable?

A) the classical music for the first half of the class
B) the silent environment for the second half of the class
C) the reading speed of both groups during the experiment
D) the test scores of both groups at the end of the experiment