Dears I would like to know the command line to: 1. plot the periodogram of a time series 2. To calculate a sazonal difference of the 7th order 3. Put the AR or MA term of the 9th order sazonal (or not-sazonal) part. 4. The significance level (P-value) for the estimated parameters of the ARMA(1,1), e.x. The default output is the parameter value and his s.e. . Thaks Fl?vio -- View this message in context: http://r.789695.n4.nabble.com/Arima-and-Sarima-Models-tp3580300p3580300.html Sent from the R help mailing list archive at Nabble.com.