Question

select the correct answer from each drop - down menu. a group of doctors are conducting an experiment to test a new nutritional supplement. they randomly selected 600 subjects, assigning 300 subjects to receive the supplement and 300 subjects to receive a placebo. the doctors are unaware of which subjects are assigned to each treatment group. this experiment is blinded because know which treatment group each subject is in. neither the subjects nor the researchers only the subjects only the researchers

Explanation:

In a blinded experiment, either the subjects or the researchers or both are unaware of which treatment group each subject is in. Here, it's stated that the doctors (researchers) are unaware of which subjects are assigned to each treatment group. The description doesn't mention subject - awareness, but given the researcher - unawareness, it is a blinded experiment. And since only the researchers' unawareness is stated, the appropriate description is that only the researchers don't know which treatment group each subject is in.

Answer:

This experiment is blinded because only the researchers know which treatment group each subject is in.