Cumulative histogram of the RMS values. The black and blue histograms show the cumulative distribution of the median pixel value, measured along the line of sight in the mosaic, and the RMS at the location of each H I-detection. The dotted grey lines at 0.28 and 0.34 mJy beam⁻¹ show the 80^th and 90^th percentiles of the cumulative distribution of H I detections, respectively. The overwhelming majority of H I detections are near the minimum RMS of the mosaic with only a small variation.