Slope of the gradients of: luminosity-weighted [Z/H] (first column); mass-weighted metallicity (second column); luminosity-weighted age (3rd column) and mass-weighted age (4th column), for the different subsamples: weakly barred (top row); unbarred (middle row) and barred galaxies (bottom row). The point on the top of the diagram indicates the mean value (weighted with the errors) and the colored error bar the rms dispersion. The black error bar shows the dispersion expected by the errors