the gold standard of research is the\n\n○ epidemiological study.\n○ controlled study.\n○ treatment and…

the gold standard of research is the\n\n○ epidemiological study.\n○ controlled study.\n○ treatment and control study.\n○ double - blind, placebo group study.

the gold standard of research is the\n\n○ epidemiological study.\n○ controlled study.\n○ treatment and control study.\n○ double - blind, placebo group study.

Answer

Brief Explanations:

In research, a double - blind, placebo group study minimizes bias. In a double - blind study, neither the participants nor the researchers know who is in the treatment or placebo group. The placebo group serves as a control to account for the placebo effect. This combination makes it the gold standard.

Answer:

double - blind, placebo group study.