The answer is "The experiment is missing a control group."
Control group, the standard to which examinations are made in an experiment. Numerous experiments are intended to incorporate a control gathering and at least one trial gatherings; truth be told, a few researchers hold the term analyze for contemplate outlines that incorporate a control gathering. In a perfect world, the control gathering and the exploratory gatherings are indistinguishable inside and out with the exception of that the test bunches are subjected to medicines or interventions accepted to affect the result of intrigue while the control amass isn't.