Distribution of the inferred mean RefSeq transcript lengths by library. (a) Histogram of the tag abundance-weighted mean transcript lengths. The abscissa unit is the mean absolute deviation (MAD) scale estimate (a robust estimate of the dispersion in the data) of all RefSeq NM transcript lengths, while the origin is set to the M-estimator of location (MEL; robust estimate of the mean) of the NM transcript lengths. If the inferred transcript lengths were unbiased, the histogram would be centered on 0 at the red star. The inferred transcript lengths were biased towards shorter transcripts. (b) Histogram of the length of all bovine RefSeq NM transcripts. The MEL of this distribution is marked with the red star and corresponds to the origin in (a). Nt, nucleotides.