Ans. is 'b' i.e. Attributable risk * Odds ratio is a measure of the strength of the association between risk factor & outcome. Diseased Not Diseased Exposed A B Not Exposed C D Odds ratio = AD/BC Relative risk = (Incidence of disease among exposed) x 1000 / (Incidence of disease among non-exposed) Attributable risk = (Incidence of disease among exposed - incidence among non-exposed) x 1000 / (Incidence among exposed) AR indicaes to what extent the disease under study can be attributed to the exposure. Population Attributable Risk = Incidence of disease in the total population - the incidence of disease among those who were not exposed attributable risk or excess risk is the difference in rate of a condition between an exposed population and an unexposed population.