Top panel: Δm₁₅ for 15 SNe Ib/c in the SDSS sample as a function of the effective wavelength of each filter in the SN rest frame (violet, green, red, dark yellow and cyan represent ugriz filters). Bluer bands decline faster than redder bands. Central panel: Same as in the top panel, the 2nd order polynomial fitted to the data (and plotted in red) corresponds to Δm₁₅(λ) = aλ² + bλ + c, where a = 5.14 × 10^-8, b = −8.41 × 10^-4 and c = 3.84. Δm₁₅ is expressed in magnitudes and λ in Å. Typical 1σ uncertainties on Δm₁₅(λ) are on the order of 0.4 mag. Vertical dashed lines indicate the effective wavelengths for the ugriz filters. Bottom panel: cumulative distribution functions for the r/R-band Δm₁₅ of SNe Ib (14), Ic (14), Ic-BL (10) and IIb (2), from the SDSS sample and from Drout et al. (2011). SDSS Δm₁₅ values are those interpolated at λ_eff(r_{z = 0}). Shaded areas indicate the uncertainties for Δm₁₅. There is no significant difference among the distributions of the different classes, with p-values >0.05.