An experimental group is a group in which members of the groups are exposed to independent variable manipulation.

The control group is a comparison group that is treated in every way like the experimental group except that the manipulated variable is absent in it.

Example: In the study by Latane and Darley, there were two experimental groups and one control group. The participants in the study were sent to three types of rooms. In one room no one was present (control groups). In the other two rooms, two persons were already seated (experimental groups). Of the two experimental groups, one group was instructed not to do anything when smoke filled in the room. The other groups was not given any instructions. After the experimental manipulation had occurred the performance of the control group measured in terms of reporting of smoke was compared with that of the experimental group. It was found that the control group participants reported in maximum members about the emergency.