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st: nlcom command for elasticity
From
HENRY AKAEZE <[email protected]>
To
[email protected]
Subject
st: nlcom command for elasticity
Date
Thu, 3 Jun 2010 06:39:34 -0700 (PDT)
Dear Statalisters,
I am doing estimation using the AIDS model. In order to estimate elasticity, I used nlcom command on an elasticity function I derived through differentiation as follows:
nlcom((-.0093/cpi)*((gdpca/cifprice1)-$b*(lagimportca-$a*laglocalca))*8.89)
The exogenous variables are CPI, CIF and the lags of import and domestic products.
However, stata complained that reference was made to X rather
than _b[X] as follows:
expression((-.0093/cpi)*((gdpca/cifprice1)-.6892200041267298*(lagimportca-.1785226557738297*laglocalca))*8.89)
contains reference to X rather than _b[X]
When evaluated at their means I got a value but without standard errors and p-value as below:
nlcom((-.0093/35)*((36/.33)-$b*(3.7-$a*14.4))*8.89)
_nl_1:(-.0093/35)*((36/.33)-.6892200041267298*(3.7-.1785226557738297*14.4))*8.89
------------------------------------------------------------------------------
importca
|
P>|t| Coef. [95% Conf. Interval]
Std. Err. t
-------------+----------------------------------------------------------------
_nl_1 -.255856 . . .
------------------------------------------------------------------------------
Could anyone help me out please. I need to know what is going on and what I must do to get values for the standard errors, t-stat and conf. interval.
Thank you,
Henry
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