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A Simple Approximation for Calculating Sample Sizes for Comparing Independent Proportions

Fleiss, Joseph L., Tytun, Alex, Ury, Hans K.·1980·Biometrics

Abstract

A simple approximation is provided to the formula for the sample sizes needed to detect a difference between two binomial probabilities with specified significance level and power. The formula for equal sample sizes was derived by Casagrande, Pike and Smith (1978, Biometrics 34 , 483-486) and can be easily generalized to the case of unequal sample sizes. It is shown that over fairly wide ranges of parameter values and ratios of sample sizes, the percentage error which results from using the approximation is no greater than 1%. The approximation is especially useful for the inverse problem of estimating power when the sample sizes are given.

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Metadata

Authors
Fleiss, J. L., Tytun, A., & Ury, H. K.
Venue
Biometrics
Publisher
JSTOR
Published
1980-06
Volume
36
Issue
2
Pages
343
ISSN
0006-341X (ISSN-L)
OpenAlex
W2053915257
Cited by
394
References
1
FWCI
4.74
Type
journal article
Language
en
Open access
closed

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CoChat. (2026). Citation check: A Simple Approximation for Calculating Sample Sizes for Comparing Independent Proportions. https://app.cochat.ai/papers/10.2307/2529990
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Fleiss, J. L., Tytun, A., & Ury, H. K. (1980). A Simple Approximation for Calculating Sample Sizes for Comparing Independent Proportions. Biometrics. https://doi.org/10.2307/2529990

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