Re: Non normality
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Re: Non normality

Dear Hermann,

Validity depends on the purpose of the analysis and the actual nature of the 

The variance components estimated by ASREML for non-normal data are not 
strictly REML.  They are the extrapolation of the REML method to non-normal
data and there has been a lot of concern that such extrapolation
does not always lead to 'correct' answers.  Of course, we usually do
not know the correct answer (unless we have simulated the data).

So, I usually use several models and am more confident if the conclusions
(or interpretation) is not modified by the model.


> X-Authentication-Warning: petidomo set sender 
to using -f
> Date: Thu, 13 Jul 2000 20:20:24 -0400
> From: "C. Balde" <>
> MIME-Version: 1.0
> To: asreml <>
> Subject: Non normality
> Content-Transfer-Encoding: 7bit
> Dear Arthur,
> Just one question: How valid are the REML estimation of variance
> components when the data don't follow a normal distribution ?
> Hermann
> --
> Asreml mailinglist archive:

Arthur Gilmour PhD        
Principal Research Scientist (Biometrics)            fax: <61> 2 6391 3899
NSW Agriculture                                           <61> 2 6391 3922
Orange Agricultural Institute             telephone work: <61> 2 6391 3815
Forest Rd, ORANGE, 2800, AUSTRALIA                  home: <61> 2 6362 0046

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