Distribution of the low-energy photon index for the 318 GRBs listed in Table 2 fitted with either the Band or CPL model and with determined . The solid (black) line shows the fit with a Gaussian. Also shown (hatched blue and red histograms) are the distributions for 274 long and 44 short GRBs, respectively, and their Gaussian fits (dot-dashed and dashed line for long and short events, respectively).