Effect of accretion variability. The sub-panels display the distributions of the correlation slope, intercept, and offset as violin plots from the Monte Carlo simulations, used to assess the impact of variability on the best-fit empirical relations in Table 1. The bars and ’x’-markers overlaid on the violin plots indicate the reported slope, intercept, and offset values for each line from Table 1. The reported uncertainties incorporate the simulated ±50% variability to the measured line fluxes to account for non-contemporaneous log(L_acc) measurements.