Which of the following can be a significant problem for correlational studies?

A) It is nearly impossible to find an effect in most studies.
B) It can be hard to tell which factor is causing the other.
C) Demand characteristics can be a significant problem.
D) Placebo effects can be a significant problem.

Correlational Studies

Studies in which the investigator analyzes the relationships among variables that were in place before the study, without manipulating those variables.

Placebo Effects

Observable or measurable changes in health or behavior resulting from the administration of a placebo, demonstrating the power of belief and expectation in the healing process.