Sample size calculations for main effects and interactions in case-control studies using Stata's nchi2 and npnchi2 functions

Catherine L. Saunders, D. Timothy Bishop and Jennifer H. Barrett
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Catherine L. Saunders: Genetic Epidemiology Division, Cancer Research UK Clinical Centre
D. Timothy Bishop: Genetic Epidemiology Division, Cancer Research UK Clinical Centre
Jennifer H. Barrett: Genetic Epidemiology Division, Cancer Research UK Clinical Centre

Stata Journal, 2003, vol. 3, issue 1, 47-56

Abstract: The non-central Chi-squared distribution can be used to calculate power for tests detecting departure from a null hypothesis. Required sample size can also be calculated because it is proportional to the non-centrality parameter for the distribution. We demonstrate how these calculations can be carried out in Stata using the example of calculating power and sample size for case-control studies of gene-gene and gene-environment interactions. Do-files are available for these calculations. Copyright 2003 by Stata Corporation.

Keywords: gene-environment interaction; gene-gene interaction; power; sample size; study design; non-central Chi-squared (search for similar items in EconPapers)
Date: 2003
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