Not much context given in this question, but I will try to explain as best to my ability.
The Placebo effect is a reaction to a placebo manifested by a lessening of symptoms or the production of anticipated side effects.
The placebo effect refers to when patients are placed in incorrect groups, which results in bias in all groups of the experiment. The placebo effect refers to an experiment where neither the participants nor the experimenters know who belongs to the treatment group and who belongs to the control group.
This is a brief explanation regarding the Placebo Effect.
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- ROR.