Before experimental drugs can be brought to market, they must undergo many rigorous trials to ensure they deliver their medical benefits effectively and safely. one method commonly used in this process is to compare the effect of a drug with that of a placebo in double-blind tests. which of the following correctly describes a double-blind test?
a. the researchers apply two-layered blindfolds to the study participants so that they cannot see whether they are receiving the drug or a placebo.
b. neither the researchers nor the study participants know who is receiving the drug and who is receiving the placebo.
c. the researchers know who is receiving the drug and who is receiving the placebo, but they do not know what the supposed effects of the drug should be.
d. the researchers do not know who receives the drug or the placebo, but the participants know and tell them later.
e. none of the above is correct.