A Researcher Is Testing the Effectiveness of a New Math

Multiple Choice

A researcher is testing the effectiveness of a new math program. The extraneous variables, such as temperature and lighting, will best be controlled by

A) randomly assigning students to rooms of varying temperature and light intensity.
B) randomly selecting the rooms in which the students will be taught.
C) making the temperature and the amount of light the same for all the rooms.
D) letting the students select the room temperature and lighting in which they are most comfortable.