Several factors influence the determination of sample size in epidemiological studies. These include:
Effect Size: The magnitude of the difference or association you expect to find. Significance Level (α): The probability of rejecting the null hypothesis when it is true (Type I error), commonly set at 0.05. Power (1-β): The probability of correctly rejecting the null hypothesis when it is false, typically set at 0.80 or 80%. Population Variability: The degree of variability in the population being studied. Study Design: The study design (e.g., cohort, case-control, cross-sectional) also affects the sample size.
