Bootstrap tests of the significance of the power-law index change with the MOP. The red line represents the power-law index obtained after matching with a 70% overlap, and the dashed lines its confidence interval. The blue distribution represents the power-law indices obtained after randomly sampling N pairs from the parent distribution (10% overlap), where N is the size of the 70% minimal overlap distribution. This random sampling has been performed 10000 times in order to obtain the distribution. This figure shows that the change in power-law index with the MOP cannot arise from a random sampling of the parent population, except for the surface density.