Research on Freight Development of Guangdong Province Based on Grey Theory Model

Table 6

Residual test results of GM (1,1) of freight volume in Guangdong Province.

Year	Water freight volume (W)		Air cargo volume (A)		Pipeline freight volume (P)
	2013	0.000	0.000	0.000	0.000	0.000	0.000
2014	−37.190	0.048	−0.130	0.058	−0.078	0.078
2015	21.270	0.027	0.000	0.000	0.031	0.031
2016	35.950	0.043	0.070	0.029	0.055	0.055
2017	−6.580	0.007	0.220	0.090	0.076	0.076
2018	−18.190	0.018	−0.120	0.040	−0.062	0.062
2019	0.170	0.000	0.103	0.034	−0.006	0.006

Source: according to the calculation criteria.