Open AccessREQUIRED SAMPLE SIZE FOR COMPARING PROPORTIONS IN TWO INDEPENDENT SAMPLES
Author(s) -
А М Гржибовский,
М А Горбатова,
А. Н. Наркевич,
К. А. Виноградов
Publication year - 2020
Publication title -
morskaâ medicina
Language(s) - English
Resource type - Journals
eISSN - 2587-7828
pISSN - 2413-5747
DOI - 10.22328/2413-5747-2020-6-3-76-83
Subject(s) - sample size determination , statistics , null hypothesis , statistical power , type i and type ii errors , statistical hypothesis testing , sample (material) , mathematics , confidence interval , computer science , chromatography , chemistry
This paper continues our series of articles on required sample size for the most common basic statistical tests used in biomedical research. Sample size calculations are rarely performed in research planning in Russia often resulting in Type II errors, i.e. on acceptance on false null hypothesis due to insufficient sample size. The most common statistical test for analyzing proportions in independent samples is Pearson’s chi-squared test. In this paper we present a simple algorithm for calculating required sample size for comparing two independent proportions. In addition to manual calculations we present a step-by-step guide on how to use WinPepi and Stata software for calculating sample size for independent proportions. In addition, we present a table for junior researchers with already calculated sample sizes for comparing proportions from 0,1 to 0,9 by 0,1 with 95% confidence level and 80% statistical power.