[R-sig-ME] How to assess significance of variance components(Please discard previous e mail... but read this one)

David Duffy David.Duffy at qimr.edu.au
Fri Nov 16 00:06:21 CET 2012

On Fri, 16 Nov 2012, Stephane Chantepie wrote:

> The major issue come from the fact that univariate models using 
> age-classes show a decrease with VA across age and the random regression 
> show an increase with age.

I was going to suggest categorizing age ;), and doing likelihood ratio 
tests using pedigreemm.  It _sounds_ like your distributional assumptions 
might need checking, or maybe you have no power to estimate these kinds of 
models, or you have to centre age.  Does phenotypic variance fall off with 
age?  Have you done diagnostic plots for poissonness? What do simple 
correlations between different classes of relatives look like?

Just 2c. David.

| David Duffy (MBBS PhD)                                         ,-_|\
| email: davidD at qimr.edu.au  ph: INT+61+7+3362-0217 fax: -0101  /     *
| Epidemiology Unit, Queensland Institute of Medical Research   \_,-._/
| 300 Herston Rd, Brisbane, Queensland 4029, Australia  GPG 4D0B994A v

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