This Webulator is based on the following sample size formula for proportions


Conversion table for percent confidence to Z
90% [Zalpha] = 1.64 91% [Zalpha] = 1.70
92% [Zalpha] = 1.75 93% [Zalpha] = 1.81
94% [Zalpha] = 1.88 95% [Zalpha] = 1.96
96% [Zalpha] = 2.05 97% [Zalpha] = 2.17
98% [Zalpha] = 2.33 99% [Zalpha] = 2.58

Only enter the numeric values without special characters for the initial population, the expected proportion, the Zalpha for the percent confidence, and the percent error, in the appropriate Webulator cells and then click on the button labelled CALCULATE to compute the sample size required to represent a proportion of a population.

Initial population Expected proportion Zalpha for the
percent confidence		 Percent error
Sample Size Numerator Denominator



For more information, please contact:

Professor William J. Montelpare, Ph.D.,
Margaret and Wallace McCain Chair in Human Development and Health,
Department of Applied Human Sciences, Faculty of Science, & Faculty of Nursing,
Health Sciences Building, University of Prince Edward Island,
550 Charlottetown, PE, Canada, C1A 4P3
e-mail wmontelpare@upei.ca
Copyright © 2002--ongoing [University of Prince Edward Island]. All rights reserved.