Fitting the mass–radius relation of embedded clusters in observations using N-body simulations. For the samples in Fig. 3, their radii were divided by 2.84, and then merged with the samples in Fig. 2. The radii of all samples were unified to the half-mass radius. The yellow dashed line is the mass–radius relation of Pfalzner et al. (2016). Dashed cyan, black, and blue lines represent the mass–radius relations of all samples, the samples in Lada et al. (1991); Carpenter et al. (1993); Lada & Lada (2003) and the samples in Carpenter (2000); Kumar et al. (2006); Faustini et al. (2009), respectively. Here, “k” is the slope of the fitting with the unit pc/M_⊙, and “r” represents the Pearson correlation coefficient.