Dear John,
Thanks for your comments! But when I tried your suggestion, the output was as the following:
Response Dist_arbre :
Df Sum Sq Mean Sq F value Pr(>F)
Poids 1 0.00010398 0.00010398 6.2910 0.0364733 *
Age 1 0.00005202 0.00005202 3.1476 0.1139652
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
I have the P-value but not the direction of the relationship, information that I had with "lm(as.matrix(Y) ~ x+z)". I could combine the results of these two tests, but it seems inelegant to me. Moreover I didn't have a total significance test as with a true MANCOVA.
An idea?!
Rémi Lesmerises, biol. M.Sc.,
Candidat Ph.D. en Biologie
Université du Québec à Rimouski
300, allée des Ursulines
remilesmerises@yahoo.ca
________________________________
De : John Fox
À : Rémi Lesmerises
Cc : "r-help@r-project.org"
Envoyé le : mercredi 17 avril 2013 10h54
Objet : Re: [R] Mancova with R
Dear Remi,
Take a look at the Anova() function in the car package. In your case, you could use
Anova(lm(as.matrix(Y) ~ x + z))
or, for more detail,
summary(Anova(lm(as.matrix(Y) ~ x + z)))
I hope this helps,
John
------------------------------------------------
John Fox
Sen. William McMaster Prof. of Social Statistics
Department of Sociology
McMaster University
Hamilton, Ontario, Canada
http://socserv.mcmaster.ca/jfox/
On Wed, 17 Apr 2013 07:47:27 -0700 (PDT)
Rémi Lesmerises wrote:
> Dear all,
>
> I'm trying to compare two sets of variables, the first set is composed exclusively of numerical variables and the second regroups factors and numerical variables. I can't use a Manova because of this inclusion of numerical variables in the second set. The solution should be to perform a Mancova, but I didn't find any package that allow this type of test.
>
> I've already looked in this forum and on the net to find answers, but the only thing I've found is the following:
>
>
> lm(as.matrix(Y) ~ x+z)
> x and z could be numerical and factors. The problem with that is it actually only perform a succession of lm (or glm), one for each numerical variable contained in the Y matrix. It is not a true MANCOVA that do a significance test (most often a Wald test) for the overall two sets comparison. Such a test is available in SPSS and SAS, but I really want to stay in R! Someone have any idea?
>
> Thanks in advance for your help!
>
> Rémi Lesmerises, biol. M.Sc.,
> Candidat Ph.D. en Biologie
> Université du Québec à Rimouski
> remilesmerises@yahoo.ca
>
> [[alternative HTML version deleted]]
>
[[alternative HTML version deleted]]