Question

the placebo effect happens when:

a. an individual interferes in an observational study.

b. an individual takes an inert substance, like a sugar pill, and feels better after taking it.

c. an individual participates in a survey and changes his or her behavior.

d. an individual is affected by the experimental treatment.

Explanation:

The placebo effect is defined as a situation where a person experiences a perceived or actual improvement in their condition after receiving a placebo (an inert substance with no therapeutic effect, such as a sugar pill). Option A refers to interference in an observational study, which is not related to the placebo effect. Option C describes response bias in surveys (changing behavior due to survey participation), not the placebo effect. Option D is too vague and does not specifically refer to the inert substance aspect of the placebo effect. Only Option B matches the definition of the placebo effect.

Answer:

B. an individual takes an inert substance, like a sugar pill, and feels better after taking it.