Hβ and C IVλ1549 profile parameter comparison as a function of luminosity. Top panels: behavior of FWHM C IVλ1549 and Hβ (upper half) and of the ratio FWHM(C IVλ1549)/FWHM(Hβ) as a function of L (lower half), for FOS (golden and pale blue) and HE sample (red and blue). The yellow band identifies the region where FWHM(C IVλ1549)/FWHM(Hβ) = 1 within the errors. Middle panels: of Hβ and C IVλ1549 (upper half), and difference as a function of L (lower half). Square symbols indicate Pop. B, circles Pop. A. Lines trace an unweighted least-squares fit for the Pop. A (black) and for Pop. B (red) sources. Bottom panels: as in top panels but for and . The vertical dotted lines join Hβ and C IVλ1549 parameters for the same object (e.g., they are not error bars).