A Novel Optimized Nonlinear Grey Bernoulli Model for Forecasting China’s GDP

Table 5

Parameters of the five grey models.

Parameter	M1	M2	M3	M4	New model (1st rolling)	New model (2nd rolling)
a	−0.070	−0.070	−0.067	−0.067	−0.067	−0.112
b	51.195	51.195	49.195	49.197	49.197	84.535
n	0.01	0.01	0.02	0.02	0.02	−0.10
α	0.5	0.5	0.497	0.496	0.496	0.494