Left panel: Molecular gas mass vs. atomic gas mass. Data are color coded according to the morphological type as in Fig. 3. The best-fit line is represented with a solid black line, and the gray-shaded region represents the 68% confidence interval of the posterior distribution of the parameters. The intrinsic dispersion (δ_intr) and correlation coefficients (namely, P and K) are reported in the lower part of each panel. Central left panel: Molecular gas fraction vs. stellar mass. Central right panel: Molecular gas fraction vs. dust-to-stellar mass ratio. Right panel: Molecular-to-total gas fraction vs. DTGR. The black cross represents the median error on both the x and y-axis.