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.