EMR

VIX

ARIMA (1, 1, 1)

ARIMAX (1, 1, 1)

ARIMA (1, 1, 1)

${\Phi }_1$

0.5547***

0.4690***

0.7601***

${\Phi }_2$

0.2008**

${\Theta }_1$

−0.9999***

−0.8949***

−0.9328***

$\beta$

0.3078***

${\sigma }^2$

102.0953

13.2295

21.4432

AIC

1838.8690

1,338.3600

1452.7390

RMSE

10.0837

3.6298

4.6213