H₂ column density as a function of sample number for the 100 positions randomly chosen to represent the Perseus molecular cloud (magenta circles). The dashed horizontal lines mark the boundaries of the ten column-density bins in which the cloud was divided, and the vertical lines enclose the ten points chosen to sample each bin. The blue circles indicate the geometrical mean of the H₂ column densities inside each bin, and their error bars indicate their dispersion. All values derived from Zari et al. (2016) data.