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Re: st: Re: vanelteren

From   Ricardo Ovaldia <[email protected]>
To   [email protected]
Subject   Re: st: Re: vanelteren
Date   Fri, 29 Jul 2005 11:02:46 -0700 (PDT)

--- Joseph Coveney <[email protected]> wrote:

>> That the medians of the pooled data are identical
> wouldn't bother me so much as 
> the difference between the asymptotic and
> permutation p-values with 256 dams.  
> Take a look at what -xtreg percent mm, i(dam) fe-
> gives you (and also take a 
> look at, say, -pnorm- on the residuals, for
> starters).  I'm guessing that 
> -xtreg, fe- (which would have been my first choice
> with this design) gives you 
> the same take-home message as what -vaneltern- does.

Yes, I first used -xtreg- and obtained a p-value of
0.018. Although the residual plot did not look to bad
using -pnorm-, they look bad on the -qnorm- plot. I
was concerned that I was not meeting the normality
assumption, therefore I opted to use a non-parametric
test. I also tried to find a transformation, but the
ones I selected found did not performed any better.   

Thank you for your help,

     percent |      Coef.   Std. Err.      z    P>|z| 
   [95% Conf. Interval]
          mm |  -.8535189   .3593038    -2.38   0.018 
  -1.557741   -.1492963
       _cons |    10.9801   .6719212    16.34   0.000 
   9.663157    12.29704
     sigma_u |  5.1721451
     sigma_e |   6.835591
         rho |  .36407729   (fraction of variance due
to u_i)

Ricardo Ovaldia, MS
Oklahoma City, OK

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