Applications of time series analysis in epidemiology: Literature review and our experience during COVID-19 pandemic

Table 1 Correlations between the variables for Model I-factors contributing to the spread among children

Variables	Cases L1	Cases L2	Variants L1	Variants L2
Cases L1	1	0.69	0.02	0.03
Cases L2	0.69	1	0.02	0.02
Variants L1	0.02	0.02	1	-0.02
Variants L2	0.03	0.02	-0.02	1

Table 2 Regression models with Auto-Regressive Integrated Moving Average (0, 1, 1) errors-Model I-overall mortality and coronavirus disease 2019

Coefficient	Estimate	Standard error
Cases L1	0.0348	0.0103
Cases L2	0.0394	0.0105
Variants L1	106.4794	134.3759
Variants L2	96.3354	134.5631
MA1	0.2594	0.1100
R2	0.953
RMSE	188.83
Bias	-2.632
MAPE	0.152

RMSE: Root mean square error; MAPE: Mean absolute percentage error.