Question

What is the purpose of the control group in an experiment?

Answer 1

Hint: Here, first we will understand the two different groups namely: - the control group and the experimental group. Further, we will know about the independent variable and the dependent variable. Finally, we will consider an example of a control group to understand the terms in a better way.

Complete step-by-step answer:
In a scientific study a control group is used to establish a cause – and – effect relationship by isolating the effect of an independent variable. The independent variable is the cause. Its value is independent of other variables in the study whereas the dependent variable is the effect whose value depends on the changes in the dependent variable.
Control groups are essential to experimental design. When we have to check the impact of a new treatment, we randomly divide participants into at least two groups: -
(i) The treatment group, also known as the experimental group, receives the treatment whose effect we are interested in.
(ii) The control group receives either no treatment, a standard treatment whose effect is already known or a fake treatment (placebo).
Let us consider an example where we are interested whether a certain new drug pill helps in relieving the anxiety levels of students studying in high school. For this we divide the students into two groups. In the first group we give the students the new drug pills and this group will be the treatment group. In the second group we provide the students with the old drug pills and this group is the control group.
After a certain interval of time we check the average change in the anxiety levels of students in the two groups and find whether the new pill is more effective or the older one.

Note: You must remember the definitions of certain terms used in the above solution. In the above solution we have considered the purpose of a control group in an experimental research. However, they are also used in non – experimental research. Control groups help us to ensure the internal validity of our research.