Distribution of the galaxy size metric Δlog(R_e), defined as the distance of the sizes R_e from the median size–mass relation at a given mass, for each galaxy population. The blue histogram shows the relative size distribution for the star-forming galaxies, while the red histogram shows the relative size distribution for the quiescent galaxies. The corresponding solid curves are the best-fit Gaussian distributions. The statistics of the mean offset (μ) and variance (σ) of each Gaussian distribution is shown at the top left.