Figures showing a correlation between various accretion parameters with log Z and R_FeII. Points are displayed using the same color-coding as in Figure 4, with their error bars. When the correlation is considered significant (r_P ≳ 0.7, corresponding to a confidence level of ≈0.01), the correlation line is shown, with its defining parameters intercept (A) and slope (B) shown with their respective errors. For each correlation are also shown the Pearson correlation coefficient, r_P, from the SLOPES program (Feigelson & Babu 1992) and the probability, P, of a spurious correlation.