COVID-19 Propagation Prediction Model Using Improved Grey Wolf Optimization Algorithms in Combination with XGBoost and Bagging-Integrated Learning

Table 2

Correlation analysis of predictor and predicted variables in sample data.

Predicted variable: cumulative number of confirmed cases in China
Predictor variable	Correlation coefficient	value	Predictor variable	Correlation coefficient	value
X1	0.034	＞0.05	X2	0.139	>0.05
X3	−0.592	<0.01	X4	0.538	<0.01
X5	−0.929	<0.01	X6	−0.874	<0.01
X7	0.536	<0.01	X8	−0.366	<0.01
X9	−0.591	<0.01	X10	0.485	<0.01
X11	−0.564	<0.01	X12	−0.536	<0.01
X13	−0.762	<0.01	X14	−0.815	<0.01
X15	−0.724	<0.01	X16	−0.574	<0.01
X17	−0.789	<0.01	X18	−0.353	<0.01
X19	−0.651	<0.01	X20	−0.820	<0.01
X21	−0.825	<0.01	X22	−0.969	<0.01
X23	−0.956	<0.01	X24	−0.726	<0.01
X25	−0.727	<0.01	X26	−0.583	<0.01
X27	0.692	<0.01	X28	−0.216	<0.01
X29	−0.474	<0.01	X30	−0.727	<0.01
X31	−0.882	<0.01	X32	−0.917	<0.01
X33	−0.915	<0.01	X34	0.715	<0.01
X35	0.596	<0.01