Probability-weighted cumulative mass profile for NGC 188. The solid dark curve represents the cumulative stellar mass M(< R) derived from our corrected catalog (M_tot = 2180 M_⊙). The intersection of the dashed red lines identifies the projected half-mass radius r_h = 5.59 pc. The shaded region denotes the volume containing 50% of the cluster’s total dynamical mass, providing the structural basis for the adopted Plummer potential.