When setting up an experiment why is it necessary to have a control group

A control group in an experiment is a group separated from the rest of the experiment (for example, there is no use of treatment on that group). It is a group where the independent variable being tested cannot influence the results. There are two types of control groups: positive and negative.

Positive - the conditions of the experiment are set to give a positive result

Negative - the conditions of the experiment are set to give a negative outcome.

To have a group to compare to the experimental group

Explanation:

I took the test k12