Which scenario best describes a double-blind study?

A) The investigator and the subjects wear blindfolds.
B) No one knows who is in the experimental or control groups
C) The subjects do not know if they are in the experimental or control groups.
D) Neither the investigator nor the subjects know who is in the experimental or control groups.
E) The investigator does not know if subjects are in the experimental or control groups.

Double-Blind Study

A research method in which both the subjects and the researchers are unaware of which group (test or control) the subjects belong to, to prevent bias.

Experimental

Pertaining to a methodical procedure carried out with the goal of verifying, falsifying, or establishing the validity of a hypothesis.

Control Groups

Groups in an experiment that do not receive the treatment being tested, enabling comparison to groups that do receive the treatment to assess its effect.