Answer to Question 1
Ans: B, C, D
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Quasi-experimental and experimental designs are used to examine causality. The gold standard for research design is the randomized, control group design, which is a type of experimental design. Retrospective, or case-controlled, studies do not examine causality.
Answer to Question 2
Ans: A
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Cohort studies, sometimes referred to as longitudinal studies, are prospective studies that monitor subjects over time to find associations between risk factors and health outcomes. In their simplest form, a sample (cohort) of subjects who are exposed to the risk factor(s) is matched with a sample of subjects not exposed to the risk factor. Cohort studies attempt to find cause-and-effect relationships. Case-control studies, also known as retrospective studies, work backward from the effect to the suspected cause. Subjects are selected on the basis of the presence or absence of the disease or outcome in question: one group of people (case-subjects) with the health problem and another group without the health problem (controls). The two groups are then compared to determine the presence of specific exposures or risk factors. A preventive study is focused on preventing the occurrence of disease in subjects. Therapeutic trials are based on secondary prevention, which focuses on limiting the spread of disease, and where the treatment (independent variable) is manipulated by the researcher.