A university trial tests a new oral supplement for reducing exam anxiety. A total of 150150 students are randomly assigned to 33 groups: supplement A, supplement B, and placebo. The trial is described as double-blind. What does "double-blind" mean in this context?

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Problem 251Multiple Choice

A university trial tests a new oral supplement for reducing exam anxiety. A total of $150$ students are randomly assigned to $3$ groups: supplement A, supplement B, and placebo. The trial is described as double-blind. What does "double-blind" mean in this context?

Neither the participants nor the researchers assessing outcomes know each student's group assignment

Only the participants do not know their group assignment, but the researchers do

Only the researchers do not know group assignments, but the participants do

Both participants and researchers know assignments, but the data analysts are blind to them

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