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

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.


Issue Date:
2003
Publication Type:
Journal Article
DOI and Other Identifiers:
st0032 (Other)
PURL Identifier:
http://purl.umn.edu/116031
Published in:
Stata Journal, Volume 03, Number 1
Page range:
47-56
Total Pages:
10

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 Record created 2017-04-01, last modified 2017-04-27

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