Figure 4
From: On the potential of models for location and scale for genome-wide DNA methylation data
Origins of inflated type I error rates of downstream hypothesis tests. Two examples of CpG sites with missing covariates (A) and strong outlier structure (B): From left to right - kernel density plot of methylation M-value, scatter plot of methylation M-value against BMI and kernel density plot of the test statistic null distribution assumed by the model lo+ (solid black line) and realized in the bootstrap samples after inclusion of genetic variants (solid blue line), for the test for a BMI effect on the scale parameter. The realized distribution approximately followed a normal distribution (dashed black line). t o b s and solid red line: test statistic from the original data without inclusion of genetic variants.