Bootstrapped distributions for C IV luminosity, FWHM, and line peak shift. Left: inter-comparison between the Al IIIλ1860 of the present sample (hatched histograms) and the C IVλ1549 FWHM distribution of the sample of Shen et al. (2011), for matching luminosity distributions (top panel). In the bottom panel, the thin blue lines show the binned distributions of bootstrap replications of the Shen et al. (2011) data; the thick blue line is their average. Right: same as for the left panels, but for peak shift.