Fe Kα EW as a function of obscuration diagnostic ratios. Color coding is similar to  3, though a dashed line is used for variable source NGC 7582 to avoid confusion with other variable sources having similar values. The statistically significant anti-correlations among all three relationships (Spearman's ρ = −0.647, −0.657, −0.645, respectively, calculated from survival analysis) indicate that obscuration is primarily responsible for X-ray attenuation. In (b), the two sources with lower limits on are plotted for illustrative purposes and were not included in the survival analysis calculations. The fitted relationships are (a) slope = −0.36 ± 0.07 dex with σ = 0.37 dex and intercept of −0.05 dex, (b) slope = −0.47 ± 0.08 dex with σ = 0.34 dex and intercept of 0.002 dex, and (c) slope = −0.41 ± 0.06 dex with σ = 0.32 dex and intercept of −1.00 dex.