Distribution of H₀ variation and its statistical significance from 1728 lightcones using the M21 scanning method (left) and the MCMC method (right) with (bottom) and without (top) mock scatter. The blue solid, red dashed, and green dash-dotted contours correspond to constraints from the L_X − T, Y_SZ − T, and M_gas − T relations, respectively. Contour levels indicate 39%, 86%, and 98.9% probability regions (equivalent to 1, 2, and 3σ in two dimensions). Blue (red) squares mark the M21 results from L_X − T (Y_SZ − T), including their measured statistical significance. Blue (red) circles show the M21 results obtained from isotropic Monte Carlo realisations for L_X − T (Y_SZ − T). While the L_X − T results fall within the 3σ contours in every configuration, the Y_SZ − T results fall well outside the contours for the no-scatter case, and roughly at the 3σ limit for the matched scatter case.