Metallicities (N2) at the locations of stripped-envelope CC SNe versus their host galaxy absolute magnitudes. SNe Ib are marked with blue circles (squares for the 3 SNe of Thöne et al. 2009), SNe Ic in red and SNe Ib/c (intermediate or uncertain type) in black. Grey stars are for GRB-SNe and gray circles for SNe Ic-BL (Modjaz et al. 2008). The displayed error bars only include the measurement errors, while all data points have an additional associated uncertainty of 0.18 dex, related to the 1σ dispersion in the N2 index calibration (shown as the black error-bar in the panel to the right). In addition, this panel shows a comparison with the corresponding mean values from Anderson et al. (2010) and Modjaz et al. (2011). Our mean values are marked with dashed-dotted lines.