TPXG                    Two Parameter Xgamma & Poisson Xgamma:
                        Regression & Distribution Functions.
dtppxg                  Probability Mass Function of the TPPXG
                        Distribution
dtpxg                   Probability Density Function of TPPXG
                        Distribution
ptppxg                  Cumulative Mass Function of the TPPXG
                        Distribution
ptpxg                   Cumulative Density Function of the TPXG
                        Distribution
qtppxg                  Inverse Cumulative Mass Function of the TPPXG
                        Distribution
qtpxg                   Inverse Cumulative Density Function of the TPXG
                        Distribution
rtppxg                  Random Numbers from the TPPGX Distribution
rtpxg                   Random Numbers from the TPGX Distribution
tppxg.mle               Maximum likelihood estimation of the TPPXG
                        distribution parameters.
tppxg.reg               Estimation of the TPPXG regression
                        coefficients.
tpxg.mle                Maximum likelihood estimation of the TPXG
                        distribution parameters.
tpxg.reg                Estimation of log-link TPXG regression
                        coefficients.
