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Table 2 Summary of statistical power to significantly detect differential methylation between cases and controls

From: Guidance for DNA methylation studies: statistical insights from the Illumina EPIC array

Sample Size Standard Deviation
0.01 0.03 0.05 0.07 0.09 0.15
Mean Difference = 2%
 100 100% 1.26% 0.03% 0.00% 0.00% 0.00%
 200 100% 21.4% 0.45% 0.04% 0.01% 0.00%
 500 100% 97.8% 17.6% 1.43% 0.19% 0.01%
 1000 100% 100% 82.7% 19.7% 3.22% 0.06%
Mean Difference = 5%
 100 100% 99.1% 24.4% 2.18% 0.29% 0.01%
 200 100% 100% 93.0% 32.0% 6.07% 0.11%
 500 100% 100% 100% 99.4% 78.4% 4.81%
 1000 100% 100% 100% 100% 100% 45.8%
  1. Presented are example power calculations for a range of scenarios, varying effect size, sample size and variance for a binary phenotype. Power calculations are for a two-sided, two-sample t-test with a significance threshold of P < 9.42 × 10− 8. The sample size is the total number of samples with a 50:50 split between groups