Histograms showing the relative uncertainty in each parameter of the young stellar population caused bythe degeneracy in the old population. Panel a: age, panel b: metallicity, panel c: extinction (A_V), and panel d: mass. We derive the best value for each parameter in each galaxy, for all considered old stellar population ages. Then we take the width of its distribution for each galaxy and compute the relative error. We see that the changes in the best values are smaller than 20% in most cases. The blue lines represent the median value of the relative error.