[R] MANCOVA in R
Hi,
I have two groups of persons, GRP0 and GRP1, on which I measured three
continuous variables: VAR1, VAR2 and VAR3.
I would like to use Mancova in R with:
- VAR1, VAR2 and VAR3 as outcome variables
- GRP={0,1} as predictor variable
- age and gender = {F,M} as covariates
What would be the correct way to formulate this model in R?
Also, since the VAR1, VAR2 and VAR3 measures were carried out on the
same persons at N=100 instances which were serially correlated, I
would like to apply permutation-based multiple-comparison correction
on the N=100 MANCOVA results I would obtain. Any help on this matter
as well would be fantastic.
Best wishes,
Michael
[[alternative HTML version deleted]]
__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
[R] Mancova with R
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 remilesmeri...@yahoo.ca [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
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 remilesmeri...@yahoo.ca 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 remilesmeri...@yahoo.ca [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Mancova with R
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 0.5202 0.5202  3.1476 0.1139652   --- Signif. codes:  0 â***â 0.001 â**â 0.01 â*â 0.05 â.â 0.1 â â 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 remilesmeri...@yahoo.ca De : John Fox j...@mcmaster.ca à: Rémi Lesmerises remilesmeri...@yahoo.ca Cc : r-help@r-project.org 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 remilesmeri...@yahoo.ca 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 remilesmeri...@yahoo.ca    [[alternative HTML version deleted]] [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Mancova with R
Dear Remi, On Wed, 17 Apr 2013 08:23:07 -0700 (PDT) Rémi Lesmerises remilesmeri...@yahoo.ca wrote: 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 0.5202 0.5202 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?! Yes, try what I suggested. The output that you show here isn't from the the Anova() function in the car package. As well, you might find it useful to read the on-line appendix on multivariate linear models, at http://socserv.socsci.mcmaster.ca/jfox/Books/Companion/appendix/Appendix-Multivariate-Linear-Models.pdf, from the book with which the car package is associated. Best, John Rémi Lesmerises, biol. M.Sc., Candidat Ph.D. en Biologie Université du Québec à Rimouski 300, allée des Ursulines remilesmeri...@yahoo.ca De : John Fox j...@mcmaster.ca À : Rémi Lesmerises remilesmeri...@yahoo.ca Cc : r-help@r-project.org 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 remilesmeri...@yahoo.ca 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 remilesmeri...@yahoo.ca [[alternative HTML version deleted]] John Fox Sen. William McMaster Prof. of Social Statistics Department of Sociology McMaster University Hamilton, Ontario, Canada http://socserv.mcmaster.ca/jfox/ __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Mancova with R
On Apr 17, 2013, at 16:47 , 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? You can fit two models and compare them with (say) fit1 - lm(as.matrix(Y) ~ x+z) fit2 - lm(as.matrix(Y) ~ x) anova(fit1, fit2, test=Wilks) or, removing terms sequentially: anova(fit1, test=Wilks) Thanks in advance for your help! Rémi Lesmerises, biol. M.Sc., Candidat Ph.D. en Biologie Université du Québec à Rimouski remilesmeri...@yahoo.ca [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. -- Peter Dalgaard, Professor Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Email: pd@cbs.dk Priv: pda...@gmail.com __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
[R] MANCOVA in R
Hello, I have subjects in 4 groups: X1, X2, X3, X4. There are 33 subjects in group X1, 35 in X2, 31 in X3, and 46 in group X4. I have 7 continuous response variables (actually integers, approximately normal) measured for each subject: Y1 to Y7, and two continuous covariates C1, C2 (they are both integers). I want to perform all pairwise comparisons for each response variable between groups. I have searched for a way to do a MANCOVA in R to no avail. I am familiar with summary.manova, and with Venables Ripley Modern Applied Statistics With S and Everitt's An R and S-Plus Companion to Multivariate Analysis. However, I am neither a statistician nor a programmer so I am finding it hard to figure this out. Can summary.manova be adapted to use covariates? What is the impact of the unbalanced design? Can I adjust for multiple comparisons? Thank you Bruno Estigarribia UNC Chapel Hill __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
