Full 2D posterior probability distribution function. The white stripe shows the tolerance interval region. The plot is for the three cases in Fig. 6 that needs a disambiguation: top left panel: DM; top right panel: DBV (different local density); bottom panel: DAV (best fit model with new scale length). Note here how DM and DAV are almost completely inside the tolerance region, while DBV is half out. DM has an ≈85% of probability to have the same observed Cepheid fraction as the Milky Way up to magnitude V = 11, while DBV is just in the ≈50%.