A control group—a population of gorillas unaffected by Ebola, separated by a river and 20 kilometers—was also observed.
The control group proved able to respond two to two and a half times faster than usual and with poor aim.
Binik cautions that it's difficult to assess the reliability of studies like this because they do not contain a control group.
in a test or trial, a group that does not receive the new treatment being studied and which is compared to the group that does receive the new treatment
control group n.
A group used as a standard of comparison in a control experiment.