st: graphing results from reg3

[Kit Baum <baum@bc.edu>]

John said:
> I was wondering how to access and use the coefficient estimates from a 
> multiline
> estimation command.
>
> Lets say my model looked like:
> -reg3 (eqn1: Y X1 X2 X3) (eqn2: Y X1 X4 X5), endog(Y X1)
>
> I'd like to make a graph of eqn1 w/ Y on the vertical axis, and X1 on 
> the horizontal.
> The intercepts are, then, the Data multiplied by the other Xs.
>
> The problem is that I've got many many of these regressions, and I'd 
> rather not have to
> cut and paste coefficient estimates from the regression output. Am I 
> making sense? Lets
> say I get an estimate of 0.25 for X1 and 0.80 for X2. I'd rather not 
> have cut-and-paste
> my way through:
> -gen intercept1 = X2*0.25 + X3*0.80
>
> Is there a way to do this by referncing the estimate directly, rather 
> than typing in the
> 0.25 business.

It seems like this could be done with predict:

reg3 (eqn1: price mpg rep78 weight) (eqn2:mpg length turn)
predict phat,eq(eqn1)
graph7 phat weight

Doesn't this do what you're describing? After all for each value of 
(X2,X3) you will have a value
of 'intercept'. You certainly can retrieve the coefficients after reg3 
and manipulate them, but I would think you
could get there more easily by using x-betahat for the specified 
equation.

Kit

*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/