Adouble-blind study is one in which neither the researchers nor the subjects know who is receiving the real treatment and who is receiving the placebo. why are studies designed in this way?

A double-blind study is used to guard against both experimenter bias and placebo effects. In other words the purpose of this kind of study is to eliminate the power of suggestion. The double-blind study keeps both researchers and participants in the dark as to who is receiving which treatment. This is important because it prevents the researchers from unintentionally tipping off the study participants, or unconsciously biasing their evaluation of the results.

fir trees are found in areas with cooler climates. fir trees have needles for leaves and remain green year-round.

your answer is "graduates" hope this