Distributions of group properties for the different samples. From top to bottom, median of the projected inter-galaxy separations, radial velocity dispersion, group r-band luminosity, virial theorem mass, crossing time, and virial theorem mass to light ratio. The probabilities that the median quantities for the Control_4B, Control_4C, and RG₄ samples are consistent with those of the CG₄ sample are listed in Table 2.