On Tue, 7 Jun 2005, Adrien BETON wrote: > Hello > I am a student working on ozone datas and i would like to use an arima > data to correlate ozone datas and gas emissions in order to predict > future ozone levels basing on other gas emissions. > Gretl should allow me to do this but I am not very used to statistics > and modelling. >
Gretl should handle rather comfortably basic stuff. What you probably need is some kind of armax model, as far as I can tell. > Therefore I have two questions : > How can I set my datas (setobs) knowing that I have values of ozone each > 30' during 6 days (48*6=288 values), gretl only recognize yearly datas ? No, but there is no support so far for infra-hour data. Your best bet is to set yout dataset to Time Series/Other. > What model do you suggest me to use in order to build a model linking > ozone to gas in order to forecast ozone levels based on the gas ? It really depends on the data. In your case, it is important to se how strong the 24-hour cycle is. > If I can t do this with gretl, what other softwares do you suggest me to > try ? > In the realm of free software, you might probably want to have a go with R (www.cran.org); R, however, is considerably more complex to use than gretl. > I hope that someone could help me :-) > I hope this helps. Riccardo `Jack' Lucchetti Dipartimento di Economia Università di Ancona jack(a)dea.unian.it http://www.econ.unian.it/lucchetti
