Instrumental neutron activation analysis (INAA), have been used for the definition of compositional groups of potteries from Justino site, Brazil,
according to the chemical similarities of ceramic paste. The outliers were identified by means of robust Mahalanobis distance. The temper effect in
the ceramic paste was studied by means of modified Mahalanobis filter. The results were interpreted by means of cluster, principal components,
and discriminant analyses. This work provides contributions for the reconstruction of the prehistory of baixo São Francisco region, and for the
reconstitution of the Brazilian Northeast ceramist population of general frame.