From: luansheng <luansheng_at_GMAIL.COM>

Date: Tue, 31 Mar 2009 21:15:27 +0800

Date: Tue, 31 Mar 2009 21:15:27 +0800

2009/4/1 Arthur Gilmour <arthur.gilmour_at_cargovale.com.au>

*> The PROBIT transformation maps a probability to an underlying scale
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*> using the Standard Normal distribution which has a variance of 1.
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*>
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*> The LOGIT transformation works in the same way, but is based on a
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*> Logistic distribution which has a variance of pi^2/3.
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*>
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*> Thus, with a logit link, the implicit residual variance on the
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*> underlying scale is the variance of the logistic distribution.
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*> This defines the scale on which the other components are estimated.
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*>
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*>
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*> On Tue, 2009-03-31 at 16:41 +0800, luansheng wrote:
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*> > In the p333 of asreml 3 user guide, it is about an analysis of footrot
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*> > as a binomial variable using the logistic link. In this example, using
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*> > pi^2/3 replace of error variance 1. I don't know the reason, anyone
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*> > tell me? thanks!
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*> >
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*> >
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*> > --
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*> > Luan sheng
*

*> > ----------------------------------------
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*> > Yellow Sea Fisheries Research Institute
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*> > Chinese Academy of Fisheries Sciences
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*> > Nanjing Road 106
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*> > Qingdao 266071
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*> > China
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*> > luansheng_at_gmail.com
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*> > luansheng_at_ysfri.ac.cn
*

*> > ----------------------------------------
*

*> >
*

*> >
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*> >
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*> >
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*> >
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*> >
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*> > This message is intended for the addressee named and may contain
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*> confidential information. If you are not the intended recipient, please
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*> --
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*>
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*> May the God and Father of the Lord Jesus Christ guide and bless you.
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*>
*

*> Arthur Gilmour
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*>
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ok. I have understand this. But why was the variance showed as 1 other

than pi^2/3 in the asr file when using logit link? I think it is more

clear if variance was showed as pi^2/3. I have got wrong heritability

because I always thought that the variance of logit was 1 from the asr

file.

-- Luan sheng ---------------------------------------- Yellow Sea Fisheries Research Institute Chinese Academy of Fisheries Sciences Nanjing Road 106 Qingdao 266071 China luansheng_at_gmail.com luansheng_at_ysfri.ac.cn ----------------------------------------Received on Wed Mar 31 2009 - 21:15:27 EST

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