Hello, I am building an ARIMA model with Gretl, and I want to forecast the changes in the value of my dependent variable for the period 2010-2012, based on my previous observations. Although I added two extra observations (of course, there are no actual values for those), I keep getting this message when I try to make a forecast for the period: There are no observations available for forecasting out of sample. If you wish, you can add observations (Data menu, Edit data), or you can shorten the sample range over which the model is estimated (Sample menu). What should I do in order to eliminate this problem? Thank you in advance.