Relations between log R_Fe and log λ_Edd for three different samples. Green circles show our N+25 reproduced data. Black, blue, and red dashed lines are our best-fit linear regressions to datasets from Hu et al. (2008), Wu & Shen (2022), and N+25, respectively. The purple solid curve is the nonlinear prescription from Du et al. (2016) found based on a sample of 63 RM super-Eddington quasars. Slopes and intercepts are shown with their 95% confidence intervals (∼2σ); numbers in brackets are the RMS scatters of each sample about the respective best-fit lines. We note that λ_Edd and ṁ are used interchangeably (see Appendix B).