Statistical methods in epidemiology, incidence, prevalence, relative risk,  attributable risk, epidemiology, types of epidemiological markers, phenotypic markers, genotypic markers, types of prevalence, point prevalence, period prevalence, applications of incidence and prevalence, measurement of risk, types of risk, risk difference, risk ratio, advantages of attributable risk, applications of attributable risk, advantages of relative risk, applications of relative risk, features of relative risk