Literature DB >> 11276038

A simple procedure to compute the sample size needed to compare two independent groups when the population variances are unequal.

J Singer1.   

Abstract

The usual methods of sample size determination which assume the homogeneity of within-group variances are not sufficiently robust against the violation of this assumption. A method using Satterthwaite's correction for unequal variances is given. It is shown that in the case of unequal variances the minimum total sample size is attained when the allocation ratio is equal to the proportion of the standard deviations. Copyright 2001 John Wiley & Sons, Ltd.

Mesh：

Year:  2001        PMID： 11276038     DOI： 10.1002/sim.722

Source DB:  PubMed          Journal:  Stat Med        ISSN： 0277-6715            Impact factor:   2.373


  7 in total

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Journal:  Braz J Phys Ther       Date:  2019-01-16       Impact factor: 3.377

2.  Non-inferiority Testing for Risk Ratio, Odds Ratio and Number Needed to Treat in Three-arm Trial.

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Journal:  Comput Stat Data Anal       Date:  2018-09-15       Impact factor: 1.681

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Journal:  Contemp Clin Trials       Date:  2013-02-24       Impact factor: 2.226

4.  Bone loss in hepatitis B virus-infected patients can be associated with greater osteoclastic activity independently of the retroviral use.

Authors:  Renata Dessordi; Ligia Moriguchi Watanabe; Mariana Palma Guimarães; Elen Almeida Romão; Ana de Lourdes Candolo Martinelli; Rodrigo de Carvalho Santana; Anderson Marliere Navarro
Journal:  Sci Rep       Date:  2021-05-13       Impact factor: 4.379

5.  Lidocaine combined with magnesium sulfate preserved hemodynamic stability during general anesthesia without prolonging neuromuscular blockade: a randomized, double-blind, controlled trial.

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Journal:  BMC Anesthesiol       Date:  2021-03-27       Impact factor: 2.217

6.  Optimal allocation to treatments in a sequential multiple assignment randomized trial.

Authors:  Andrea Morciano; Mirjam Moerbeek
Journal:  Stat Methods Med Res       Date:  2021-09-23       Impact factor: 3.021

7.  Laboratory animals and respiratory allergies: the prevalence of allergies among laboratory animal workers and the need for prophylaxis.

Authors:  Erica Ferraz; Luisa Karla de Paula Arruda; Ericson Bagatin; Edson Z Martinez; Andrea A Cetlin; Christian S Simoneti; Amanda S Freitas; José A B Martinez; Marcos C Borges; Elcio O Vianna
Journal:  Clinics (Sao Paulo)       Date:  2013-06       Impact factor: 2.365
  7 in total

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