How is relative risk calculated in epidemiology?

Relative risk is a measure used in epidemiology to compare the risk of an event occurring in two different groups. It is specifically utilized to quantify the likelihood of developing a disease or outcome among groups with different levels of exposure to a risk factor.

The correct answer represents the formula for calculating relative risk, which involves the incidence of the outcome in the exposed group compared to the incidence in the unexposed group. In this formula, "a" represents the number of individuals who developed the outcome and were exposed to the risk factor, "b" represents the number of individuals who were exposed but did not develop the outcome, "c" is the number of individuals who were not exposed but developed the outcome, and "d" is the number of individuals who were not exposed and did not develop the outcome.

Thus, the relative risk is calculated as follows:

[

\text{Relative Risk} = \frac{a/(a+b)}{c/(c+d)}

]

This ratio indicates how the risk of the outcome in the exposed group (a/(a+b)) compares to the risk in the unexposed group (c/(c+d)). A relative risk greater than 1 suggests increased risk associated with the exposure, while a relative risk less