library(TSA)
data(lynx)
arima1=arima(log(lynx),order=c(1,0,0))
arima1
Rsq=1-.6106/var(log(lynx))
Rsq
tsdiag(arima1)
acf(arima1$residuals)
pacf(arima1$residuals)
eacf(arima1$residuals)
arima2=arima(log(lynx),order=c(3,0,1))
arima2
tsdiag(arima2)
arima3=arima(log(lynx),order=c(3,0,11))
arima3
fixed=rep(NA,15)
fixed[5:13]=0

arima4=arima(log(lynx),order=c(3,0,11),fixed=fixed)
arima4