Table 2. Linear regression analysis for previous seasonal influenza-like illness and selected variables by cross-correlation analysis from the 40^th week of 2010 to the 52^nd week of 2019.

Forecast week	Variable	LR 1 Beta[P-value]	LR 2 Beta[P-value]	LR 3 Beta[P-value]	LR 4 Beta[P-value]
2 weeks	ILI—South Korea (before 50 week)	0.591[<0.001]			0.255[<0.001]
	Total GT—South Korea (present)		0.789[<0.001]		0.690[<0.001]
	Adj. R-squared	0.331	0.744		0.794
30 weeks	ILI—South Korea (before 22 week)	0.591[<0.001]			0.470[<0.001]
	Total INF—Argentina (present)		0.063[<0.001]		0.052[<0.001]
	Average Vapor Pressure—South Korea (present)			0.994[<0.001]	0.047[0.783]
	Adj. R-squared	0.331	0.513	0.303	0.712

Beta, Beta coefficient; GT, Google Trends; INF, Influenza; ILI, Influenza-like illness; LR, Linear regression