Stellar masses (top left), V₀ (top right), and T_eff (bottom left) vs. the Spearman’s correlation coefficient. Bottom right panel: T_eff vs. γ scatter plot. Stars with different correlation between the optical and X-ray variability are marked with different symbols as shown in the labels. The horizontal dotted lines mark the median values. All the plots suggest that the stars in the “anti correlated” group are on average less massive than those in the other two groups.