BTS | Table 3 - Negative Binomial Regressions for Number of Person-Trips: All Purposes and Recreational Purposes

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BTS Home > Publications > Journal of Transportation and Statistics > Volume 3 Number 3 > Paper 3

Table 3
Negative Binomial Regressions for Number of Person-Trips: All Purposes and Recreational Purposes

	Variable	Beta	SE	t-stat	P-value	Negative binomial regression	Poisson regression
Dependent variable: number of person-trips for all purposes	Constant	1.672	0.012	138.00	0.000
	HH members per vehicle owned	0.255	0.004	59.20	0.000
	Income per household member	�16E-06	2.77E-07	�.40	0.000
	Population density	�42E-06	6.10E-07	�25	0.000
	Vehicle age	�014	0.001	�.80	0.000
	Weekend day indicator	0.100	0.007	13.50	0.000
	SUV indicator	0.045	0.012	3.85	0.000
	Pickup indicator	�164	0.011	�.90	0.000
	Minivan indicator	0.302	0.011	28.50	0.000
	Over-dispersion parameter	0.351	0.004	97.10	0.000
Log-likelihood Function for number of person-trips for all purposes	Constant only					�1,113.3	�0,951.3
	Convergence					�7,983.1	�8,642.7
	Pseudo-R²					0.026	0.076
Dependent variable: number of person-trips for recreational purposes	Constant	0.485	0.021	22.80	0.000
	HH members per vehicle owned	0.204	0.008	25.90	0.000
	Income per household member	�14E-06	4.73E-07	�60	0.000
	Population density	�12E-06	1.09E-06	�60	0.000
	Vehicle age	�018	0.001	�.60	0.000
	Weekend day indicator	0.590	0.014	41.40	0.000
	SUV indicator	0.005	0.021	0.20	0.814
	Pickup indicator	�292	0.019	�.20	0.000
	Minivan indicator	0.308	0.020	15.70	0.000
	Over-dispersion parameter	1.009	0.011	93.40	0.000
Log-likelihood function for number of person-trips for recreational purposes	Constant only					�,460.37	�,6536.4
	Convergence					�,612.10	�,753.51
	Pseudo-R²					0.022	0.064

Number of observations: 41,538 vehicles
Model form: Number of person-trips ~ negative binomial with expected value exp(β′X) and non-negative over-dispersion parameter

Table 3 Negative Binomial Regressions for Number of Person-Trips: All Purposes and Recreational Purposes

Table 3
Negative Binomial Regressions for Number of Person-Trips: All Purposes and Recreational Purposes