The control group in the experiment are the classes where the teacher does not greet the students
A control group in an experiment is made up of groups of people that do not receive the experimental treatment.
The purpose of a control group is to allow the researcher study one variable at a time.
Victor is conducting an experiment on if positively greeting children as they enter the classroom reduces problem behaviours.
The experimental treatment here is positively greeting the students.
The group that do not receive this experimental treatment are referred to as the control group.
At the end of the experiment, Victor would compare the behaviours of the students in the control group with the behaviour of those who were part of the experimental group to see if greeting reduced problem behaviours.
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