Researchers wanted to determine if having a refrigerator in the bedroom is associated with obesity. The researchers administered a questionnaire to 353 twelve-year-old adolescents. After analyzing the results, the researchers determined that the body mass index of the adolescents who had a refrigerator in their bedroom was significantly higher than that of the adolescents who did not have a refrigerator in their bedroom. Complete parts (a) through (e) below.
Why is this an observational study?
(A) This is an observational study because the researchers observe the behavior of the individuals in the study without trying to influence an explanatory variable of the study.
(B) This is an observational study because the researchers try to influence the outcome of the study.
(C) It is not an observational study
