The fact that many times researchers unintentionally influence the outcome of their studies implies the existence of

A) experimenter bias.
B) a placebo effect.
C) sampling bias.
D) social desirability.

Experimenter Bias

A process where the scientists performing the research influence the results, consciously or unconsciously, in a way that introduces errors or specific outcomes.

Placebo Effect

The phenomenon in which a person experiences a physiological or psychological improvement after being treated with an inert or ineffective substance or intervention.

Sampling Bias

A bias that occurs when a sample is not representative of the population from which it was drawn, potentially leading to inaccurate conclusions.