The is a method in which neither the research participants nor the researchers know whether the participants are getting the treatment or a placebo.

The double-blind study is a method in which neither the research participants nor the researchers know whether the participants are getting the treatment or a placebo. Is a tool of the scientific method used to prevent research results can be influenced by the placebo effect or observer bias.

answer; /// all of the above;

answer; evidence; reverseremand;