Table 4 Characteristics of ARIMAX models: coefficients, standard errors, P value for coefficients and Ljung-Box test of residuals, MAPE, AIC.

From: Using Baidu Search Engine to Monitor AIDS Epidemics Inform for Targeted intervention of HIV/AIDS in China

Model

Variable

Parameter

Lag

Coefficients

Standard error

P value

Ljung-Box test

AIC

MAPE

Model 1

ARIMA

MA

1

0.939

0.117

<0.0001

0.269

1184.78

7.57%

MA

2

−0.283

0.117

0.0185

SAR

12

0.779

0.098

<0.0001

Model 2

ARIMA + Baidu CI

AR

1

−0.644

0.114

<0.0001

0.155

839.42

6.11%

SMA

12

−0.100

0.292

0.0013

  1. ARIMA: autoregressive integrated moving average model, ARIMAX: ARIMA with external variables, AIC: Akaike information criterion, MAPE: mean absolute percentage error, MA: moving average, SAR: seasonal autoregressive, SMA: seasonal moving average.
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