Comparisons between four methods of gas mass calibration based on dust SED or RJ-tail continuum as presented in Section 3 and labeled at top right. We divide the sources into three categories based on their longest available rest-frame ALMA wavelength (denoted as ﹩{\lambda }_{\mathrm{rest}}﹩): ﹩{\lambda }_{\mathrm{rest}}\leqslant 160\,\mu {\rm{m}}﹩ (red), ﹩160\lt {\lambda }_{\mathrm{rest}}\leqslant 250\,\mu {\rm{m}}﹩ (orange), and ﹩{\lambda }_{\mathrm{rest}}\gt 250\,\mu {\rm{m}}﹩ (blue), which also correspond to the three same color-shaded areas in Figure 2, respectively. In each panel, the dashed line is a one-to-one line, and the parallel dotted lines indicate a factor of two variation. The embedded histogram plotted in each Y-versus-X scatter plot is the normalized distribution of ﹩{\mathrm{log}}_{10}(Y/X)﹩. See discussion in Section 3.3.