st: marginal effects of interacting variables

[Mehmet Beceren <mbeceren@hbs.edu>]

Hi,
I have a regression with interacting variables in the following form: Y = a 
+ bX1 + cX2 + zX1X2
And I would like to estimate the total marginal effect (total derivative) 
of X1 and the standard error of the total derivative.
The derivative at the mean of the variables will be b + z* meanX1*meanX2

Does anyone know a quick command to get the SE of the total derivative 
after such a regression? Manual calculations become harder as the number of 
interacting variables increase.

Mehmet

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