Histogram from Scientific Research

Variation of the residual distribution along the process of the two-step robust regression. In Step 1, as the iteration increases in the IRLS algorithm for computing the robust M-estimate, most residuals converge towards 0 bp, while a fraction of residuals are still between 0 and 69 bp. In Step 2, the read coordinates are estimated by OLS on the data excluding the subset of outliers identified in Step 1. The final residuals of all data are clustered into two peaks exactly at 0 and 69 bp, which means the outliers have been separated out.

DOI