Maps of the median Hδ_A + Hγ_A and its scatter (computed as one-half of the 16th–84th percentile range) for SDSS-DR7 galaxies with S/N ≥ 10 in 2D bins in the plane of concentration vs. absolute r-band magnitude M_r. The maps in the top row are obtained with the original fiber indices, while those in the bottom row are computed with aperture-corrected indices. Iso-density contours are overlaid, including fractions of 0.05, 0.20, 0.50 (thick contour), 0.75, 0.95, and 0.99 of the sample, respectively.