An analysis for these results is made one replica at a time and figure shows examples of the distribution of the relative binding free energies which are found in the results. We plot these results with a calculation of the skewness and excess kurtosis. The skewness characterizes the symmetry of the distribution and kurtosis is related to the tails of the distribution, where higher values of the kurtosis indicates the presents of a significant number of outliers in the Here we report the "excess kurtosis" as the kurtosis-3. The excess kurtosis measures the deviation of the kurtosis with respect to the kurtosis one would expect for a Gaussian distribution. Figure shows distributions of the binding free energy for two randomly selected ligand transformations; these distributions are approximately symmetric in terms of both skewness and excess kurtosis. If we examine all values of skewness and excess kurtosis as plotted in figure as a function of the relative binding free energy it can be seen that although many results look approximately Gaussian there are distributions with significant skew and kurtosis. Overall these results imply the presence of non-normal distributions. This is consistent with previous work which has reported the same non-Gaussian distributions for relative binding free energy calculations .