Table 2.

Residual white noise test results of each prediction model

Model	Box-Ljung
	χ2	P
Original sequence—SARIMA(2,1,0)(1,1,2)12	0.030	0.860
IMF1—SARIMA(2,0,2)(0,1,2)12	0.240	0.630
IMF2—ARMA(2,2)	0.010	0.930
IMF3—SARIMA(2,1,1)(0,0,1)12	0.050	0.820
Res—ARIMA(2,2,1)	1.740	0.190