[R] Chi-square test
Sergio Ferreira Cardoso
sergio.ferreira-cardoso at umontpellier.fr
Mon Jan 23 13:02:03 CET 2017
Dear David and John,
Thank you for your replies. Indeed I'm using ape and nlme packages. Here it is:
Analysis of Deviance Table (Type II tests)
Df Chisq Pr(>Chisq)
mass 1 0.1756 0.6752
activity 2 0.5549 0.7577
agility 4 3.2903 0.5105
Anyway, I have the help I was looking for. Thank you vey much.
----- Mensagem original -----
> De: "Fox, John" <jfox at mcmaster.ca>
> Para: "Sergio Ferreira Cardoso" <sergio.ferreira-cardoso at umontpellier.fr>
> Cc: "R-help list" <r-help at r-project.org>
> Enviadas: Sábado, 21 De Janeiro de 2017 6:09:22
> Assunto: Re: [R] Chi-square test
> Dear Sergio,
> You appear to have asked this question twice on r-help.
> Anova() has no specific method for “gls” models (I assume, though you don’t say
> so, that the model is fit by gls() in the nlme package), but the default method
> works and provides Wald chi-square tests for terms in the model. I don’t
> understand the model formula x ~ 1 + 2 + 3 + x, however, and so I have no idea
> what gls() would do with this model, other than report an error. Perhaps you
> can show us the output — or, better yet, provide a reproducible example.
> As a general matter, for 1-df terms in an additive model, the 1-df chi-square
> values reported by Anova() will simply be the squares of the corresponding Wald
> statistics (labelled “t” I believe) reported in the summary of the model.
> Although the p-value is from the upper tail of the chi-square distribution, the
> test is inherently two-sided.
> John Fox, Professor
> McMaster University
> Hamilton, Ontario, Canada
> Web: http::/socserv.mcmaster.ca/jfox
>> On Jan 20, 2017, at 8:36 AM, Sergio Ferreira Cardoso
>> <sergio.ferreira-cardoso at umontpellier.fr> wrote:
>> Dear all,
>> Anova() for .car package retrieves Chi-square statistics when I'm testing a
>> model the significance of a multivariate .gls model
>> gls(x~1+2+3+x,corBrownian(phy=tree), ...).
>> Is this Chi-square a two-sided test?
>> Thank you.
>> [[alternative HTML version deleted]]
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
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