Hello everyone, I am just trying to understand how the Arimax function works, so my questions are: 1. If I have a univariate time series of sales and sales are dependent upon, say inflation rates, then my xreg would be inflation rates right? 2. Now is I have historial data on sales (from january 2000 to december 2010) then my xreg argument would be a historical time series of inflation rates on the same time frame? (from january 2000 to december 2010?) 3. If I want to predit, say 5 years of monthly data (60 periods) using the exogenous variable (in this particular case inflation rates) then that means I would have to have a a 60 period forecast of inflation rates and that would be my newxreg argument? Any guidance will be greatly appreciated, Best regards, Paul [[alternative HTML version deleted]]