Question

Which of the following is an advantage of an observational study over a sample survey? A)Observational studies are not dependent on people’s responses, which may not be truthful.
B)Observational studies involve the random selection of subjects.
C)Observational studies do not manipulate variables.
D)Observational studies do not involve treatments.

Answer 1

I think it is B)Observational studies involve the random selection of subjects.