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Sample size formula with a continuous outcome for unequal group sizes and unequal variances
Author(s) -
Schouten Hubert J. A.
Publication year - 1999
Publication title -
statistics in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.996
H-Index - 183
eISSN - 1097-0258
pISSN - 0277-6715
DOI - 10.1002/(sici)1097-0258(19990115)18:1<87::aid-sim958>3.0.co;2-k
Subject(s) - sample size determination , outcome (game theory) , statistics , mathematics , sample (material) , group (periodic table) , econometrics , mathematical economics , physics , chemistry , chromatography , quantum mechanics
Guenther derived a simple formula for the accurate computation of equal sample sizes when the two‐sample t ‐test with pooled variance estimate is used. In the present paper, the Guenther formula is generalized to the case of unequal sample sizes. In addition, the case of unequal variances is considered. Copyright © 1999 John Wiley & Sons, Ltd.