[R-sig-eco] fourthcorner() with missing data

[Stéphane Dray]

Hello,

the method does not consider missing values. The best solution would be 
to estimate missing values to fill the . For this estimation, you can 
either use the nipals method (nipals function in ade4 with rec = TRUE) 
or use the missMDA package. The second approach is better.

Cheers.

On 08/01/2013 16:40, Beth Atkinson wrote:
>
> Hello,
>
> I want to do a fourth corner analysis but I have missing data. I have 
> 169 species from 32 plots. There are 4 habitat types and I'm looking 
> at 8 traits. However, I don't have trait data for all species for each 
> trait (each trait has data for at least 80% of species).
>
> The function fourthcorner in ade4 returns an error message about NAs. 
> Is there a way around this? If I remove species that have data missing 
> for any trait, I lose around a third of the species.
>
> Thanks,
>
> Beth
>
> --------------------------------------------------------
> Beth Atkinson
>
> PhD student
> Community Ecology Group
> School of Biological Sciences
> University of Bristol
> Woodland Road
> Bristol
> BS8 1UG
>
> http://www.bristol.ac.uk/biology/people/beth-atkinson/
>
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>


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Stéphane DRAY (stephane.dray at univ-lyon1.fr)
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