Hello people, i have two questions: 1) I´m studying a sarima(x) model about beer consumption with a dummy variable to a local holiday that happen in february or march,and the dummy aim to control this (1 in the month with this particular holiday and 0 without it). In gretl, can i estimate this model using the 'command' below(using the dummy as exogenous variable)? arima p d q; P D Q; dependent_variable dummy_variable 2) The other is a model about net revenues from a local oil company, where i want to use a sarimaX with brent price(the barrel) as exogenous variable. In this case, both variables(net revenues and brent price) have to be stationary? In gretl, can i estimate it using the command below? arima p d q; P D Q; dependent_variable brent_oil     Thanks all,   regards.     Natal,Brazil. ____________________________________________________________________________________ Veja quais são os assuntos do momento no Yahoo! +Buscados http://br.maisbuscados.yahoo.com