Explanation: Control group is the group of people that are not the members of the experimental treatment rather they are selected on random basis because they have high similarity with the actual participant who get through the experiment .
The situation mentioned in the question describes about the participants that are indulged in quiet setting are subjected to control group.As the control group participant are similar with the actual members of experiment in the noisy setting.
The participants in the quiet setting were assigned to the experimental group as this type of group is where participants are use in participating with the experiment in order to test and investigate the outcome of the study that is being conducted.
