The correct answer for this question is Designed experiment.
A person experiences the placebo effect when their physical or mental health seems to get better after receiving a placebo or "dummy" treatment. A treatment that seems to be real but is intended to have no therapeutic benefit is referred to as a placebo. The Latin word for placebo means "I will please."
One of the most popular hypotheses holds that a person's expectations are what causes the placebo effect. It's possible that the body's chemistry can produce results comparable to what a drug might have produced if a person anticipates a pill to do something.
