Measure of [α/Fe] on SDSS stacked spectra and associated best-fit spectra. Left panel: Elemental abundances as a function of the velocity dispersion for ETGs. Empty symbols correspond to literature measurements of different α elements. The diamonds indicate average [α/Fe] from Thomas et al. (2010), up and down triangles are oxygen and magnesium as measured by Johansson et al. (2012), and squares show the [Mg/Fe] trend of Conroy et al. (2014). The filled purple circles show the best-fitting (but misleading) pPXF+MILES solution. Right panels: Spectra for the lowest (top panel) and highest (bottom panel) σ bin. The observed stacked spectrum is given in black and the best-fit spectrum in cyan. The residuals are shown in blue. We also provide a zoom-in into the Mgb region.