Bootstrapping probability density histogram of the N = 10⁴ slopes fitted using the Alstott et al. (2014) KS metric, measured for data sets generated using the metric parameters obtained for our sample of 205 cores. The black and red vertical lines indicate the resulting slope coefficient of α = −0.98 ± 0.10 and the getsf fitted slope of α = −0.95 ± 0.04 (orange area corresponding to 1σ, see Sect. 5.1). 1, 2, and 3σ dispersions are estimated from the bootstrapping (shaded gray areas). The Salpeter slope (dashed vertical magenta line) is rejected with a probability of 99.98%.