Which of the following is an example of a double-blind study?
A. Participants are randomly assigned to a treatment group or a control group
B. Participants and researchers both know which group participants are assigned to
C. Participants do not know which group they are assigned to, but researchers do
D. Both participants and researchers do not know which group participants are assigned to
A double-blind study is a research design in which neither the participants nor the researchers know which group participants are assigned to. This is done to minimize bias and ensure that the results of the study are as objective as possible. In a double-blind study, the treatment and control groups are randomly assigned, and the participants and researchers are unaware of which group each participant is assigned to. Option a) is an example of a randomized controlled trial, which is a common research design, but it is not necessarily double-blind. Option b) is an example of an open-label study, in which both the participants and the researchers know which group each participant is assigned to. Option c) is an example of a single-blind study, in which the participants do not know which group they are assigned to, but the researchers do.
Therefore, the Correct Answer is D.