Relation between the X-ray excess variance and the X-ray Eddington ratio, λ_X ≡ L_{2 − 10 keV}/L_Edd. Left: Full sample. Right: RM-only subsample. Cyan points show detections; red triangles show upper limits. Dark-blue stars indicate medians in λ_X bins (shown for visualisation only). The dashed black lines show the best-fit relations; the grey shaded areas show the 1σ confidence intervals. Slopes and intercepts are indicated in each panel.