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Exact sample size needed to detect dependence in 2 x 2 x 2 tables.
Jianliang Dai1, Li Li, Sangkyu Kim
1Genetics Department, University of Georgia, Athens, Georgia 30602, USA.
Biometrics
|December 15, 2007
Summary
Researchers developed methods to calculate sample sizes for genetic studies on longevity. These tools help design efficient sampling strategies and identify significant single nucleotide polymorphisms (SNPs) for future research.
Area of Science:
- Genetics
- Biostatistics
- Gerontology
Background:
- The Georgia Centenarian Study investigates factors contributing to exceptional longevity.
- Centenarians and young controls are classified by age, ethnicity, and genetic markers (SNPs).
- Determining adequate sample size is crucial for detecting significant associations in complex genetic studies.
Purpose of the Study:
- To provide methodologies for calculating minimum sample size needed to detect dependencies in 2x2x2 tables.
- To enable researchers to design efficient sampling strategies and select informative SNPs for longevity studies.
- To compare the computational efficiency and accuracy of exact and Markov Chain Monte Carlo (MCMC) methods for sample size determination.
Main Methods:
- Developed methodologies for sample size calculation based on Fisher's exact test for 2x2x2 tables.
- Utilized exact computation and Markov Chain Monte Carlo (MCMC) simulation for sample size determination.
- Employed parallel computing techniques for the exact sample size problem and serial computing for the MCMC method.
Main Results:
- The study provides tools for sample size determination in genetic studies of longevity.
- The MCMC method offers a faster alternative to exact methods, being on average 10.16 times faster.
- MCMC-derived sample size results are reliable for larger sample sizes (hundreds) but require caution for smaller samples.
Conclusions:
- The developed methodologies and tools aid in designing efficient genetic studies for exceptional longevity.
- The MCMC approach provides a computationally efficient alternative for sample size calculations in large studies.
- Accurate sample size determination is essential for the successful identification of genetic factors influencing longevity.
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