Final answer:
Relative risk is a probability statement used by epidemiologists to measure the association between a disease and a specific risk factor. It compares the incidence of a health-related event in exposed and unexposed groups, with ratios greater or less than one indicating higher or lower risk, respectively.
Step-by-step explanation:
When studying the association between a disease and a specific risk factor, epidemiologists use relative risk as a probability statement. Relative risk, also known as the risk ratio, compares the incidence of a health-related event in a group exposed to the risk factor with the incidence in a group not exposed. Ratios greater or less than one indicate higher or lower risk, respectively, while a ratio close to one suggests no difference in risk. This measure helps in evaluating if there is an association between a risk factor and its impact on health.