Nothing is more speedy than Google.

For example, the following online textbook explains everything you need

On 02/11/11 06:51 AM, Sam Buxton wrote:
Hi all,

I am having problems doing a number of things in gretl. I was just 
wondering if anyone could help if they know how to produce the following 
models in gretl

1) exponential smoothing
2) moving average
3) naive model
4) bass diffusion model.

Thanks a speedy response would be greatly apprecieated.


Pierre Chaussé
Assistant Professor
Department of Economics
University of Waterloo