pause on
use phillips
reg unem inf year
tsset year
arima unem inf year, ar(1 ) ma(1 2 )
arima unem inf year, arima(1,0,2)
arima unem inf year, arima(1,1,2)
clear
use fertil3
reg gfr pe ww2 pill
tsset t
arima gfr pe ww2 t pill,arima(2,0,2) 
arima gfr pe ww2 t pill,arima(2,1,2)