Table 5.

LR: Linear Regression; RMSE: Root Mean Squared Error; MAE: Mean Absolute Error; MAPE: Mean Absolute Percentage Error.

ID	Meth.	Variable Groups	TRAIN (80%)				TEST (20%)
			adj. R2	RMSE	MAE	MAPE	RMSE	MAE	MAPE
1	LR	smoking + state + EQI + emissions	0.617	10.067	7.507	12.133	11.155	8.281	13.901
2	LR	smoking + state + EQI	0.612	10.168	7.556	12.241	11.167	8.259	13.858
3	LR	smoking + state + emissions	0.602	10.273	7.697	12.478	11.416	8.579	14.332
4	LR	state	0.527	11.239	8.198	13.324	11.792	8.664	14.414
5	LR	emissions	0.322	13.543	10.494	17.089	13.996	10.818	18.316
6	LR	smoking	0.308	13.724	10.367	17.401	14.777	11.083	19.289
7	LR	EQI	0.211	14.639	11.098	18.633	15.297	11.429	20.338