An

interventional study does not involve giving a piece of advice, a vaccine or medication.

Double

blinding means that neither investigators nor patients know which study group

they belong to.

An odds

ratio of 1 suggests that the risk factor might be a possible cause of the

disease.

Ecological

studies’ results as well as conclusions apply to individuals.

Ethics is

of concern while conducting a study.

A case

series study is aimed at describing the demographics, clinical presentations,

prognosis, and other characteristics.

Ecological

studies are particularly useful for comparing the health of populations in

different places or at different times.

Case

series study did not contribute to the identification of HIV in the early

1980’s.

Cross

sectional studies can be called prevalence studies.

Relative

risk is the main measurement used in a Cohort Study.