Results of the KS test applied to the chemical abundances of all four halo groups defined in this work. These results concern the case where the in situ contamination that has [Al/Fe] > 0.0 was removed from all groups. Brown regions indicate that the null hypothesis was not rejected (i.e. there is no difference between the groups). The green regions indicate that the null hypothesis was rejected (there is a difference between the groups). Only elements where some difference was detected are shown. For all other elements, the KS test indicates no difference between the groups.