Cumulative distribution function (CDF) of 3 GRB parameters: E_po, photon fluence, and peak photon flux for the three classes of Fermi GRBs defined in Fig. 1. Black solid line: 43 GRBs with a redshift; green dashed line: 253 GRBs with or without a redshift that may be compatible with the E_pi – E_iso relation at some redshift; red dash-dotted line: 29 GRBs without a redshift that are incompatible with the E_pi – E_iso relation at any redshift (outliers). This figure emphasizes the larger E_po and smaller photon fluence of outliers.