Fifty patients on dialysis are divided into two groups. One group receives an
experimental drug to fight cancer comma the other a placebo. After two years comma kidney functionality is measured.
Does the description correspond to an observational study or an experiment?
A.
The study is an observational study
because the study examines individuals in a sample comma
but does not try to influence the response variable.
B.
The study is an observational study because the researchers control one variable to determine the effect on the response variable.
C.
The study is an experiment because the study examines individuals in a sample, but does not try to influence the variable of interest.
D.
The study is an experiment
because the researchers control one variable to determine
the effect on the response variable.
D.
The study is an experiment because the researchers control one variable (the administration of the experimental drug or placebo) to determine the effect on the response variable (kidney functionality).
D.
The study is an experiment because the researchers control one variable (administering the experimental drug) to determine the effect on the response variable (kidney functionality).