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Re: st: Xaxis transformation after logging variable


From   Francisco Augusto <francisco.augusto.7@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Xaxis transformation after logging variable
Date   Tue, 21 Aug 2012 16:24:18 +0100

Thanks for the quick answer. It worked! (I am sorry for the trivial
question, though)

The reference I was talking about was Nick Cox, Speaking Stata:
Graphing Distributions, 2004, The Stata Journal, pp 77

For the other question, I am sorry for the lack of information.

I am trying to use the Prentice 1974 "A log gamma model and its
maximum likelihood estimation" Biometrika Trust. In this approach the
parameter k is transformed to q =  k ^ (-1/2) with support to k of 0
to +infinity , parametrization also used by Lawless 1980 "Inference in
the generalized gamma and log gamma Distributions" and applied in
Cabral & Mata 2003 "On evolution of firm size distribution: facts and
theory".

With this approach I intended to apply the extended generalized gamma
distribution to the logged variable, and by that obtaining estimates
for the different parameters. After that, I was trying to regress the
logged variable on other variables assuming the logged variable
follows the extended generalized distribution.

Should I "repost" the previous question? Is this information enough?

Thank you very much for all the help,
Francisco Augusto




On Tue, Aug 21, 2012 at 3:50 PM, Nick Cox <njcoxstata@gmail.com> wrote:
> "Cox showed" (even guessing and narrowing it down to me) is not a
> precise reference. But if your axis variable is log_10(variable) and
> you want labels in terms of variable, you can just go something like
>
> ... xla(0 "1" 1 "10" 2 "100")
>
> This is well documented at -help axis label options- and is no sense
> limited to showing kernel density estimates.
>
> I guess people ignored your previous question because it wasn't clear
> (there are several possible generalisations oof the gamma
> distribution) and was based on an incomplete reference. Still true.
>
> Nick
>
> On Tue, Aug 21, 2012 at 3:27 PM, Francisco Augusto
> <francisco.augusto.7@gmail.com> wrote:
>> Dear Statalist,
>>
>> I am dealing with a small problem: I am doing kernel (kdensity) of a
>> logged variable and I would like to rearrange the Xaxis to be in the
>> original scale and on a 10 exponential order (like 1 10 100 1000
>> 10000, of the original values). I have seen a solution for the first
>> part of the problem: Cox showed a command to get the original scale on
>> the xaxis after logging a variable. Nevertheless, I don't know how to
>> have the  1 10 100 1000 10000 order.
>>
>> Plus, I am still struggling to find a solution for the Prentice 1974
>> generalized gamma approach. It would be so nice for someone to present
>> a possible solution!
>>
>> Thanks in advance!
>> Francisco Augusto
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