ation, 'control' can be used as a noun meaning either the group
which is not manipulate
d by the experimenter
, or a measure taken to prevent confound
s (or counfounding variable
s) from influencing the results. Example: "The experimental
group took the drug we're testing, while the control
group was treated exactly the same way, except that the pill they were given contained no active ingredient."
Also a verb meaning to take such measures. Example: "We thought that age of the subjects might introduce a confound, so we controlled
for that by selecting only subjects born in May of 1944."