Re: [Gretl-users] ARIMA with season length of 3 months

2010-06-04 Thread Ignacio Diaz-Emparanza
El jue, 03-06-2010 a las 12:05 -0700, deepak bhatia escribió:
> I am new to gretl and have been using the windows/UI version for a
> couple of days now. Could someone help me understand how/where can I
> specify the seasonal difference to be 3 or any number. The UI does not
> allow me to specify a seasonal difference (lag) parameter (I am
> assuming that it performs a 12 month seasonal difference when I
> specify a seasonal ARIMA model by default).
>  

The periodicity of the data is what defines the type of seasonal length.
If you have monthly data, periodicity is 12 and the seasonal difference
is y(t)-y(t-12) if your data are quarterly, periodicity is 4 and the
seasonal difference is y(t)-y(t-4).

Gretl admits periodicity 1 (annual), 4 (quarter), 12 (month) and 52
(week) having as reference period (for defining the seasonals cycles)
the year, diary periodicity with 5 days, 6 days and 7 days, taking as
reference the week, and hourly taking the day as reference. There is
also the possibility of defining decennial data and user-defined
periodicity.

When you build your dataset with gretl you may specify the periodicity
when gretl asks for the type of data (time series/cross section/panel)
and you select time series. If you have imported your data from other
source you can change the periodicity by selecting "Time series" in the
menu "/Data/Dataset structure".



-- 
Ignacio Diaz-Emparanza  
DEPARTAMENTO DE ECONOMÍA APLICADA III (ECONOMETRÍA Y ESTADÍSTICA)
UPV/EHU
Avda. Lehendakari Aguirre, 83 | 48015 BILBAO
T.: +34 946013732 | F.: +34 946013754
www.ea3.ehu.es 




Re: [Gretl-users] ARIMA with season length of 3 months

2010-06-04 Thread artur bala
Hi,
Through UI, just follow the menu path : Model/Time series/ARIMA and 
specify the seasonal lag you need.
Otherwise, try to open gretl console and type in : /help arima/, to get 
more information on arima command
Cheers,
artur


deepak bhatia a écrit :
> I am new to gretl and have been using the windows/UI version for a 
> couple of days now. Could someone help me understand how/where can I 
> specify the seasonal difference to be 3 or any number. The UI does not 
> allow me to specify a seasonal difference (lag) parameter (I am 
> assuming that it performs a 12 month seasonal difference when I 
> specify a seasonal ARIMA model by default).
>  
>  
> 
>
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> Gretl-users mailing list
> Gretl-users(a)lists.wfu.edu
> http://lists.wfu.edu/mailman/listinfo/gretl-users




[Gretl-users] ARIMA with season length of 3 months

2010-06-03 Thread deepak bhatia
I am new to gretl and have been using the windows/UI version for a couple of
days now. Could someone help me understand how/where can I specify the
seasonal difference to be 3 or any number. The UI does not allow me to
specify a seasonal difference (lag) parameter (I am assuming that it
performs a 12 month seasonal difference when I specify a seasonal ARIMA
model by default).
I am new to gretl and have been using the windows/UI version for a couple of days now. Could someone help me understand how/where can I specify the seasonal difference to be 3 or any number. The UI does not allow me to specify a seasonal difference (lag) parameter (I am assuming that it performs a 12 month seasonal difference when I specify a seasonal ARIMA model by default).