Upper panel: fractions of 3061, 1637, and 2478 red galaxies within C1, C2, and C3, respectively, as a function of the δ. The δ-bins correspond to the quartiles of the δ distribution for the whole sample, and the fractions are normalised to the total number of galaxies in the same sub-class, i.e. for each sub-class the fractions in δ bins sum up to 100%. The solid line corresponds to the weighted fit. The shaded stripes around lines display 1σ of the fit. The error bars correspond to the median absolute deviation on this and all the remaining plots. The slope of the fit is given in the legend. Bottom panel: as for the top panel, but for the mass-matched sample. The M_star distribution for each red sub-class is the same.