Establecer un modelo VAR para las variables de la base de datos ‘uschange’.

Datos del modelo:

series<-(uschange)
autoplot(uschange[,1:2], ylab = "Valores")

ts.plot(series[,1:2], xlab="Tiempo",col=c(1,2))

Búsqueda y selección de los parámetros:

a <- VARselect(uschange[,1:2], lag.max=15,type="trend")
a$selection
## AIC(n)  HQ(n)  SC(n) FPE(n) 
##      3      3      1      3

Creación de los modelos:

modelo1<-VAR(uschange[,1:2],p=3,type=c("trend"))
modelo3<-VAR(uschange[,1:2],p=1,type=c("trend"))
summary(modelo1)
## 
## VAR Estimation Results:
## ========================= 
## Endogenous variables: Consumption, Income 
## Deterministic variables: trend 
## Sample size: 184 
## Log Likelihood: -385.38 
## Roots of the characteristic polynomial:
## 0.8886 0.5506 0.5506 0.4563 0.2912 0.2912
## Call:
## VAR(y = uschange[, 1:2], p = 3, type = c("trend"))
## 
## 
## Estimation results for equation Consumption: 
## ============================================ 
## Consumption = Consumption.l1 + Income.l1 + Consumption.l2 + Income.l2 + Consumption.l3 + Income.l3 + trend 
## 
##                  Estimate Std. Error t value Pr(>|t|)    
## Consumption.l1  0.2346575  0.0799935   2.933 0.003796 ** 
## Income.l1       0.1008841  0.0552239   1.827 0.069412 .  
## Consumption.l2  0.1931296  0.0835806   2.311 0.022003 *  
## Income.l2      -0.0035172  0.0579583  -0.061 0.951679    
## Consumption.l3  0.2701792  0.0800381   3.376 0.000905 ***
## Income.l3       0.0078077  0.0549405   0.142 0.887153    
## trend           0.0011036  0.0005638   1.958 0.051860 .  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Residual standard error: 0.6092 on 177 degrees of freedom
## Multiple R-Squared: 0.6405,  Adjusted R-squared: 0.6263 
## F-statistic: 45.05 on 7 and 177 DF,  p-value: < 2.2e-16 
## 
## 
## Estimation results for equation Income: 
## ======================================= 
## Income = Consumption.l1 + Income.l1 + Consumption.l2 + Income.l2 + Consumption.l3 + Income.l3 + trend 
## 
##                  Estimate Std. Error t value Pr(>|t|)    
## Consumption.l1  0.5074199  0.1153193   4.400 1.87e-05 ***
## Income.l1      -0.2460717  0.0796113  -3.091 0.002318 ** 
## Consumption.l2  0.0634472  0.1204906   0.527 0.599148    
## Income.l2      -0.0618530  0.0835532  -0.740 0.460109    
## Consumption.l3  0.4073755  0.1153836   3.531 0.000529 ***
## Income.l3      -0.0268248  0.0792028  -0.339 0.735248    
## trend           0.0017128  0.0008128   2.107 0.036497 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Residual standard error: 0.8782 on 177 degrees of freedom
## Multiple R-Squared: 0.4602,  Adjusted R-squared: 0.4389 
## F-statistic: 21.56 on 7 and 177 DF,  p-value: < 2.2e-16 
## 
## 
## 
## Covariance matrix of residuals:
##             Consumption Income
## Consumption      0.3689 0.2022
## Income           0.2022 0.7683
## 
## Correlation matrix of residuals:
##             Consumption Income
## Consumption      1.0000 0.3799
## Income           0.3799 1.0000
summary(modelo3)
## 
## VAR Estimation Results:
## ========================= 
## Endogenous variables: Consumption, Income 
## Deterministic variables: trend 
## Sample size: 186 
## Log Likelihood: -408.648 
## Roots of the characteristic polynomial:
## 0.5838 0.3287
## Call:
## VAR(y = uschange[, 1:2], p = 1, type = c("trend"))
## 
## 
## Estimation results for equation Consumption: 
## ============================================ 
## Consumption = Consumption.l1 + Income.l1 + trend 
## 
##                 Estimate Std. Error t value Pr(>|t|)    
## Consumption.l1 0.4626250  0.0714742   6.473 8.58e-10 ***
## Income.l1      0.1375815  0.0553825   2.484 0.013883 *  
## trend          0.0022217  0.0005588   3.976 0.000101 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Residual standard error: 0.654 on 183 degrees of freedom
## Multiple R-Squared: 0.574,   Adjusted R-squared: 0.567 
## F-statistic: 82.18 on 3 and 183 DF,  p-value: < 2.2e-16 
## 
## 
## Estimation results for equation Income: 
## ======================================= 
## Income = Consumption.l1 + Income.l1 + trend 
## 
##                  Estimate Std. Error t value Pr(>|t|)    
## Consumption.l1  0.6969795  0.0998422   6.981 5.23e-11 ***
## Income.l1      -0.2075006  0.0773637  -2.682  0.00798 ** 
## trend           0.0025844  0.0007806   3.311  0.00112 ** 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Residual standard error: 0.9135 on 183 degrees of freedom
## Multiple R-Squared: 0.405,   Adjusted R-squared: 0.3953 
## F-statistic: 41.53 on 3 and 183 DF,  p-value: < 2.2e-16 
## 
## 
## 
## Covariance matrix of residuals:
##             Consumption Income
## Consumption      0.4189 0.2554
## Income           0.2554 0.8243
## 
## Correlation matrix of residuals:
##             Consumption Income
## Consumption      1.0000 0.4347
## Income           0.4347 1.0000

Evaluación de los modelos:

aic1<-summary(modelo1)$logLik;aic1
## [1] -385.3802
aic2<-summary(modelo3)$logLik;aic2
## [1] -408.6483

Por medio del criterio de información de Akaike, se determina que el modelo más eficiente para las variables utilizadas es el número 3, dado que su resultaado es de -408.6483, que es más negativo que el otro modelo utilizado.

Datos del modelo por cada variable:

Consumption

summary(modelo1,equation="Consumption")
## 
## VAR Estimation Results:
## ========================= 
## Endogenous variables: Consumption, Income 
## Deterministic variables: trend 
## Sample size: 184 
## Log Likelihood: -385.38 
## Roots of the characteristic polynomial:
## 0.8886 0.5506 0.5506 0.4563 0.2912 0.2912
## Call:
## VAR(y = uschange[, 1:2], p = 3, type = c("trend"))
## 
## 
## Estimation results for equation Consumption: 
## ============================================ 
## Consumption = Consumption.l1 + Income.l1 + Consumption.l2 + Income.l2 + Consumption.l3 + Income.l3 + trend 
## 
##                  Estimate Std. Error t value Pr(>|t|)    
## Consumption.l1  0.2346575  0.0799935   2.933 0.003796 ** 
## Income.l1       0.1008841  0.0552239   1.827 0.069412 .  
## Consumption.l2  0.1931296  0.0835806   2.311 0.022003 *  
## Income.l2      -0.0035172  0.0579583  -0.061 0.951679    
## Consumption.l3  0.2701792  0.0800381   3.376 0.000905 ***
## Income.l3       0.0078077  0.0549405   0.142 0.887153    
## trend           0.0011036  0.0005638   1.958 0.051860 .  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Residual standard error: 0.6092 on 177 degrees of freedom
## Multiple R-Squared: 0.6405,  Adjusted R-squared: 0.6263 
## F-statistic: 45.05 on 7 and 177 DF,  p-value: < 2.2e-16 
## 
## 
## 
## Covariance matrix of residuals:
##             Consumption Income
## Consumption      0.3689 0.2022
## Income           0.2022 0.7683
## 
## Correlation matrix of residuals:
##             Consumption Income
## Consumption      1.0000 0.3799
## Income           0.3799 1.0000

Income

summary(modelo1,equation="Income")
## 
## VAR Estimation Results:
## ========================= 
## Endogenous variables: Consumption, Income 
## Deterministic variables: trend 
## Sample size: 184 
## Log Likelihood: -385.38 
## Roots of the characteristic polynomial:
## 0.8886 0.5506 0.5506 0.4563 0.2912 0.2912
## Call:
## VAR(y = uschange[, 1:2], p = 3, type = c("trend"))
## 
## 
## Estimation results for equation Income: 
## ======================================= 
## Income = Consumption.l1 + Income.l1 + Consumption.l2 + Income.l2 + Consumption.l3 + Income.l3 + trend 
## 
##                  Estimate Std. Error t value Pr(>|t|)    
## Consumption.l1  0.5074199  0.1153193   4.400 1.87e-05 ***
## Income.l1      -0.2460717  0.0796113  -3.091 0.002318 ** 
## Consumption.l2  0.0634472  0.1204906   0.527 0.599148    
## Income.l2      -0.0618530  0.0835532  -0.740 0.460109    
## Consumption.l3  0.4073755  0.1153836   3.531 0.000529 ***
## Income.l3      -0.0268248  0.0792028  -0.339 0.735248    
## trend           0.0017128  0.0008128   2.107 0.036497 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Residual standard error: 0.8782 on 177 degrees of freedom
## Multiple R-Squared: 0.4602,  Adjusted R-squared: 0.4389 
## F-statistic: 21.56 on 7 and 177 DF,  p-value: < 2.2e-16 
## 
## 
## 
## Covariance matrix of residuals:
##             Consumption Income
## Consumption      0.3689 0.2022
## Income           0.2022 0.7683
## 
## Correlation matrix of residuals:
##             Consumption Income
## Consumption      1.0000 0.3799
## Income           0.3799 1.0000