Model void scaling functions |$\chi ({\bar{N}}{\bar{\xi }})$|⁠. The solid (blue) line shows the negative binomial model (equation A14); the doted (black) line shows the minimal model (equation A5); the short dashed/long dashed (green) line shows the quasi-equilibrium model (equation A20); the dot–dashed (red) line shows the Schaeffer or lognormal model (equation A21); the long dashed (cyan) curve shows the gravitational instability prediction (Section A6); and the short dashed (cyan) curves show the smoothed gravitational instability result for effective power index n = −3, −2, −1, 0 and +1 (top to bottom).