Random assignment is used to control for
A) subject bias.
B) the placebo effect.
C) selection bias.
D) experimenter bias.

Question

Quizplus · Accepted Answer

Random assignment is used to control for selection bias, which occurs when there is a systematic difference between the groups being studied that could impact the outcome of the study. Random assignment helps to ensure that members of each group are similar in all ways except for the variable of interest, which strengthens the internal validity of the study. Subject bias, the placebo effect, and experimenter bias are all potential sources of error in a study but are not controlled for by random assignment.

Random Assignment Is Used to Control for