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st: RE: Calculate confidence intervals for log-log models
From 
 
Jason Ferris <[email protected]> 
To 
 
"[email protected]" <[email protected]> 
Subject 
 
st: RE: Calculate confidence intervals for log-log models 
Date 
 
Tue, 5 Mar 2013 20:26:56 +0000 
Hi Nick,
Sorry for my ambiguity.  And thank you for your response.
Before, I start writing my own code to do this I will attempt to clarify.
Yes I transformed both Y and X with a natural log transformation ln(y) and ln(x)
I then regress lny on lnx
OLS example of a result:
------------------------------------------------------------------------------
         lny |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
         lnx |   2.105722   .0817271    25.77   0.000     1.942802    2.268642
       _cons |  -3.032146   .4274653    -7.09   0.000    -3.884282   -2.180009
------------------------------------------------------------------------------
To calculate a 10% change on lnx (with confidence intervals) when I type
lincom 1.1^lnx - I get the message 'not possible with text'
I would like to construct a table highlighting percentage changes in lny with a series of percentage changes (10,25...) in lnx
Kind regards,
Jason
On Tue, 5 Mar 2013 12:49:28 +0000 Nick Cox <[email protected]> wrote:
Not really clear what you are doing but I guess that you are
transforming first. Either way, something like
_b[ln(y)]
makes no sense to Stata as
ln(y)
can't be a variable name.
I fear you need to write your own code.
Nick
On Tue, Mar 5, 2013 at 11:30 AM, Jason Ferris <[email protected]> wrote:
> I have run a series of log-log OLS models - ln(y)=ln(x)+cons - and would like to present a table of percentage change at 10%, 25%, 50%, & 75% with corresponding changes in the confidence intervals.
>
> Is there a way to do this in Stata or a ado file that I could utilise.
>
> When trying to use lincom (.e.g., 1.1^_b[ln(x)] - I get a 'not possible with test' error.  What are the alternatives besides doing it all by hand?
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