Section: AP Psychology

2) In order to study the effects of noise on worker productivity, researchers have one group of participants work in a noisy room and a second group work in a quiet room. To ensure that any differences in the productivity of the two groups actually result from the different noise levels to which the groups are exposed, the researchers would use:

1. the case study.
2. correlational measurement.
3. naturalistic observation.
4. replication.
5. random assignment.

To reduce possible bias in the experimental design, the participants must be randomly assigned to the control group or the experimental group.