Definition of control group in an experiment?

Answer 1

A control group is what you are comparing your test agent against. For example, if you are testing to see if a new fuel works more efficiently that an existing one, you would test the existing fuel under the same conditions as the new fuel.

Answer 2

In a scientific study a sample must be run along with the test sample or samples to account for the normal BASELINE or BACKGROUND NOISE that results from an unaltered sample. This is "subtracted from each sample run in the test to account for unknown factors that may be falsely altering the test results.

For instance if you are testing various samples of tap water mixed with other chemicals to determine the calcium concentration, a "Control" (a.k.a. "Blank") is run with JUST tap water and no chemical added. Since tap water often has traces of calcium in it, the control will show how much of the readings are due to the calcium present in the tap water. This can then be subtracted from each other sample yielding useful data.

Answer 3

It means the part of the experiment that always stays the same, like if you are testing how tall plants grow in different temperatures, your control would be the type of plant...

Answer 4

a group that will not produce a reaction. it is to insure that the experiment is correct. Normally it is the one that contains water. Not a tested fluid like starch, bovine blood, or such.