Correlations between the MCV coefficient ρ_Pearson and fundamental AGN parameters for the Seyfert 1 sample. (a)–(c) ρ_Pearson as a function of black hole mass (M_BH), bolometric luminosity (L_bol), and Eddington ratio (ξ_Edd). Symbol and color definitions are the same as in Figure 3. The linear regression results for the RQ population are shown by dashed (NLSy1) and solid (BLSy1) lines. (d) Distribution of RQ Seyfert 1 (RQ Seyfert 1) galaxies in the M_BH–L_bol plane. The grid represents bins of 0.3 × 0.3 dex, with only bins containing ≥20 sources shown. (e) Median ρ_Pearson calculated within each bin, with color coding indicating the dominant variability trend (BWB vs. RWB). Diagonal lines represent loci of constant ξ_Edd, with values increasing from the bottom right to the top left.