High Quality Content by WIKIPEDIA articles! X-12-ARIMA is the U.S. CEnsus Bureau's software package for seasonal adjustment. IT can be used together with gretl, which provides a graphical user interface for X-12-ARIMA. X-12-ARIMA is the successor to X-11-ARIMA. IN statistics and econometrics, and in particular in time series analysis, an autoregressive integrated moving average (ARIMA) model is a generalisation of an autoregressive moving average (ARMA) model. THese models are fitted to time series data either to better understand the data or to predict future points in the series. THey are applied in some cases where data show evidence of non-stationarity, where an initial differencing step (corresponding to the "integrated" part of the model) can be applied to remove the non-stationarity.