My annual time series has following ACF/PACF structure.
Based on what ARIMA model should be selected here? Exponential decreasing of ACF --> AR(4) probably? Or because of periodical ACF maybe SMA? Or because of signifiant 1st and 8th PACF --> SAR? Or because it is an annual time series I should not consider seasonal models? What is the best approach here, please?
Time series is stationery.
forecast::auto.arima()
for R) much more than the Box-Jenkins approach. $\endgroup$