Table 2.

ARCH effect of the observations and residuals of the selected three models with LM test at various lags.

Lags	Observed values		SARIMA model		NAR model		LSTM model
	LM-test	P	LM-test	P	LM-test	P	LM-test	P
1	54.599	<0.001	1.869	0.172	0.262	0.609	0.002	0.961
3	73.920	<0.001	2.669	0.446	2.823	0.420	0.440	0.932
6	72.753	<0.001	3.575	0.734	2.972	0.812	3.338	0.765
9	71.185	<0.001	4.703	0.859	14.741	0.098	5.216	0.815
12	73.136	<0.001	14.080	0.296	11.422	0.493	7.294	0.838
15	71.275	<0.001	14.566	0.483	30.219	0.011	10.241	0.804
18	69.282	<0.001	15.566	0.623	32.252	0.020	13.735	0.746
21	67.505	<0.001	20.645	0.481	34.845	0.029	0.7462	0.881
24	73.785	<0.001	21.094	0.633	34.774	0.072	14.815	0.926
27	71.487	<0.001	25.263	0.560	36.360	0.108	18.172	0.898
30	68.830	<0.001	27.984	0.571	38.706	0.133	19.899	0.919
33	66.153	<0.001	32.378	0.498	41.990	0.136	22.538	0.915
36	64.210	<0.001	33.766	0.575	46.280	0.117	23.631	0.944