title: Sample size estimation in epidemiologic studies.
abstract: This review basically provided a conceptual framework for sample size calculation in epidemiologic studies with various designs and outcomes. The formula requirement of sample size was drawn based on statistical principles for both descriptive and comparative studies. The required sample size was estimated and presented graphically with different effect sizes and power of statistical test at 95% confidence level. This would help the clinicians to decide and ascertain a suitable sample size in research protocol in order to detect an effect of interest.
authors.affiliation: Department of Social Medicine and Health, Babol University of Medical Sciences, Babol, Iran.
authors.forename: Karimollah
authors.initials: K
authors.lastname: Hajian-Tilaki
keywords: Binary outcome; Comparative studies; Continuous outcome; Effect size; Sample size; Statistical power