Determine whether the study is an observational study or an experiment.
-A researcher obtained a random sample of 100 smokers and a random sample of 100 nonsmokers. After interviewing all 200 participants in the study, the researcher compared the rate of depression among the
Smokers with the rate of depression among nonsmokers.
A)observational study
B)experiment

Question

Quizplus · Accepted Answer

The researcher did not manipulate any variables or assign any groups, but instead observed and compared rates of depression among two pre-existing groups (smokers and nonsmokers). This fits the definition of an observational study. This study is an observational study because the researcher is merely observing and comparing the rates of depression among smokers and non-smokers without manipulating any variables. In an experiment, the researcher would need to manipulate one variable (e.g. have smokers quit smoking) and compare the effect on the rates of depression.

Determine Whether the Study Is an Observational Study or an Experiment