Nickel Price Forecast Based on the LSTM Neural Network Optimized by the Improved PSO Algorithm

Table 4

The Ljung–Box test results of residual sequence of ARIMA(1, 1, 2).

Lag	AC	Q	-value
1.0	0.026972	0.083684	0.772366
2.0	−0.027064	0.168704	0.919108
3.0	−0.229964	6.363354	0.095210
4.0	0.057894	6.759599	0.149151
5.0	0.122480	8.549676	0.128431
6.0	0.022287	8.609507	0.196759
7.0	−0.109559	10.069091	0.184692
8.0	−0.134496	12.289901	0.138730
9.0	−0.055056	12.665653	0.178328
10.0	0.069653	13.272957	0.208808