[Gretl-users] Re: Gretl-users Digest, Vol 30, Issue 14

[Riccardo (Jack) Lucchetti]

On Fri, October 27, 2006 20:03, Thiago Marzagão wrote:
> Thank you for your reply.
>
> The point is that I'd like to constrain the fitted values (and not the
> observed ones) of the dependent variable.
>
> The problem is that my depedent variable cannot "physically" (i.e., in real
> world situations) extrapolate a certain range of values (thus all my
> observed values lie within this range) but when I run the regression some of
> the fitted values are, in fact, outside this range (although the general fit
> of the model is good). So I need a kind of Tobit model, but I need to
> specify not only the lower bound but also the upper bound of the range. The
> Tobit command in GRETL constrains the lower bound to zero (whenever the
> fitted values are negative), but it does not specify an upper bound (and it
> does not allow me to specify a lower bound other than zero).
>
> Best regards,
>
> Thiago
>

The tobit command we have now only handles the "plain vanilla" case. However,
it should be possible to set up the model you want by using the "mle" command.
See chapter 15 of the manual for details.

HTH,


Riccardo (Jack) Lucchetti
Dipartimento di Economia
Facoltà di Economia "G. Fuà"
Ancona