When a theory is tested experimentally, it is called a controlled experiment. An independent variable (the cause) is systematically modified in a controlled experiment, and the dependent variable (the effect) is measured; all other factors are controlled.
The researcher can implement (define) the variables under investigation so that they can be measured objectively. The quantitative data may be analyzed to discover if the experimental and control groups vary in some way.
Control Group in An Experiment
In studies, scientists compare two groups: a control group and an experimental group that is similar in every way but one: experimental manipulation.
The control group is not exposed to the independent variable under research, unlike the experimental group, and hence serves as a baseline against which any improvements in the experimental group may be measured.
We can be certain that any variations between the experimental and control groups are attributable to experimental manipulation rather than chance because the sole difference between them is experimental manipulation.
Participants should have an equal probability of participating in each condition if they are randomly assigned to independent variable groups. The goal of random allocation is to avoid bias in the experiment’s execution.
Extraneous Variables in an Experiment
The researcher wishes to be sure that the changes in the dependent variable are due to the modification of the independent variable.
As a result, any other factors that may cause the dependent variable to change must be managed. Extraneous or confusing factors are these additional variables. Wherever feasible, extraneous factors should be controlled, since they may be relevant enough to give alternative explanations for the effects.