In the PROC ARIMA step, you estimate ARIMA models for PRICE and INCOME before estimating the model for SALES, as shown in the following statements: proc arima data=a; identify var=price(1); estimate ...

The X11 procedure provides seasonal adjustment of time series using the Census X-11 or X-11 ARIMA method. The X11 procedure is based on the U.S. Bureau of the Census X-11 seasonal adjustment program ...