The statement that explains why randomized controlled trials are often "double blind" is as follows: to decrease bias by ensuring both the participants and researchers do not know who is receiving the treatment and who is not (option B).
<h3>What is a double blinded experiment?</h3>
Double-blinded experiments are forms of scientific testing in which some information is withheld from two different parties.
In summary, neither the tester nor the subjects tested know which are the control items and which are the test items.
A double blinded is conducted to reduce or eliminate bias between the participants and researchers.
Therefore, the statement that explains why randomized controlled trials are often "double blind" is as follows: to decrease bias by ensuring both the participants and researchers do not know who is receiving the treatment and who is not.
Learn more about double-blind at: brainly.com/question/5303449
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