title: [Practical aspects regarding sample size in clinical research].
abstract: The knowledge of the right sample size let us to be sure if the published results in medical papers had a suitable design and a proper conclusion according to the statistics analysis. To estimate the sample size we must consider the type I error, type II error, variance, the size of the effect, significance and power of the test. To decide what kind of mathematics formula will be used, we must define what kind of study we have, it means if its a prevalence study, a means values one or a comparative one. In this paper we explain some basic topics of statistics and we describe four simple samples of estimation of sample size.
authors.affiliation: Hospital de Especialidades del CMN El Fénix, Mérida, Yuc.
authors.forename: B
authors.initials: B
authors.lastname: Vega Ramos
authors.forename: O
authors.initials: O
authors.lastname: Peraza Yanes
authors.forename: G
authors.initials: G
authors.lastname: Herrera Correa
authors.forename: S
authors.initials: S
authors.lastname: Saldívar Toraya
mesh_terms: D018401:Sample Size
vernacular_title: Aspectos prácticos sobre el tamanño de la muestra en 1a investigación clínica.