Re: [R] Multiple Comparisons-Kruskal-Wallis-Test: kruskal{agricolae} and kruskalmc{pgirmess} don't yield the same results although they should do (?)

2014-05-16 Thread David Winsemius
On May 16, 2014, at 2:07 PM, Tham Tran wrote: > Dear Mr. Dalgaard, You do realize that was a posting from 2012, right? > > Could you help me know the name of post-hoc multi-comparaison test mentioned > in kruskal function of agricolae package? There are multiple such tests mentioned on that fu

Re: [R] Multiple Comparisons-Kruskal-Wallis-Test: kruskal{agricolae} and kruskalmc{pgirmess} don't yield the same results although they should do (?)

2014-05-16 Thread Tham Tran
Dear Mr. Dalgaard, Could you help me know the name of post-hoc multi-comparaison test mentioned in kruskal function of agricolae package? Thank you in advance. Tham Tran -- View this message in context: http://r.789695.n4.nabble.com/Multiple-Comparisons-Kruskal-Wallis-Test-kruskal-agricolae-

Re: [R] multiple comparisons with generalised least squares

2012-11-08 Thread mikachu
Ariel THANK YOU for posting this. worked great for me just pasting this part into R Ariel wrote > model.matrix.gls <- function(object, ...) > model.matrix(terms(object), data = getData(object), ...) > > > model.frame.gls <- function(object, ...) > model.frame(formula(object), data

Re: [R] multiple comparisons for GAMs

2012-08-07 Thread peter dalgaard
On Aug 7, 2012, at 18:48 , Bird_Girl wrote: > I have looked into using glht (‘multcomp’ package) to do multiple comparisons > for a model fit with GAM {mgcv} but after reading the description of the > ‘multcomp’ package, I believe this method only applies to parametric models > and linear hypothe

Re: [R] multiple comparisons for GAMs

2012-08-07 Thread Bird_Girl
I have looked into using glht (‘multcomp’ package) to do multiple comparisons for a model fit with GAM {mgcv} but after reading the description of the ‘multcomp’ package, I believe this method only applies to parametric models and linear hypotheses. When I ran the code glht(model,linfct….) I got a

Re: [R] Multiple Comparisons-Kruskal-Wallis-Test: kruskal{agricolae} and kruskalmc{pgirmess} don't yield the same results although they should do (?)

2012-08-07 Thread greatest.possible.newbie
I see.. So apparently the different functions are doing the same thing! :-) Besides I didn't know the groups should have about the same size. Thank you four your time Mr. Dalgaard. -- View this message in context: http://r.789695.n4.nabble.com/Multiple-Comparisons-Kruskal-Wallis-Test-kruskal-ag

Re: [R] Multiple Comparisons-Kruskal-Wallis-Test: kruskal{agricolae} and kruskalmc{pgirmess} don't yield the same results although they should do (?)

2012-08-03 Thread peter dalgaard
On Aug 3, 2012, at 18:49 , David L Carlson wrote: > Generally multiple comparisons are conducted after a test for a significant > difference among any of the groups. For your data > >> kruskal.test(x[,1]~x[,2]) > >Kruskal-Wallis rank sum test > > data: x[, 1] by x[, 2] > Kruskal-Wal

Re: [R] Multiple Comparisons-Kruskal-Wallis-Test: kruskal{agricolae} and kruskalmc{pgirmess} don't yield the same results although they should do (?)

2012-08-03 Thread David L Carlson
From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > project.org] On Behalf Of peter dalgaard > Sent: Friday, August 03, 2012 5:59 AM > To: greatest.possible.newbie > Cc: r-help@r-project.org > Subject: Re: [R] Multiple Comparisons-Kruskal-Wallis-Test: > kruskal{agricolae

Re: [R] Multiple Comparisons-Kruskal-Wallis-Test: kruskal{agricolae} and kruskalmc{pgirmess} don't yield the same results although they should do (?)

2012-08-03 Thread peter dalgaard
On Aug 3, 2012, at 11:33 , greatest.possible.newbie wrote: > Thank you for your answer. > The p.adj argument in the kruskal()-function doesn't seem to change > anything... Not even the "bonferroni"-method although it is described as the > most conservative one (multiplying all p-values with the n

Re: [R] Multiple Comparisons-Kruskal-Wallis-Test: kruskal{agricolae} and kruskalmc{pgirmess} don't yield the same results although they should do (?)

2012-08-03 Thread greatest.possible.newbie
Thank you for your answer. The p.adj argument in the kruskal()-function doesn't seem to change anything... Not even the "bonferroni"-method although it is described as the most conservative one (multiplying all p-values with the number of comparisons). I suppose the kruskal()-function is not workin

Re: [R] multiple comparisons for GAMs

2012-08-03 Thread peter dalgaard
On Aug 2, 2012, at 21:09 , Bird_Girl wrote: > Hi, > > I have a question regarding whether it is possible to do post hoc tests on a > model fit with GAM {mgcv}. My response variable is abundance (no. > individuals per plot), and I have one continuous predictor (light) and one > factor (height) w

Re: [R] Multiple Comparisons-Kruskal-Wallis-Test: kruskal{agricolae} and kruskalmc{pgirmess} don't yield the same results although they should do (?)

2012-08-03 Thread peter dalgaard
On Aug 3, 2012, at 07:42 , greatest.possible.newbie wrote: > I am doing multiple comparisons for data that is not normally distributed. > For this purpose I tried both functions kruskal{agricolae} and > kruskalmc{pgirmess}. It confuses me that these functions do not yield the > same results altho

[R] Multiple Comparisons-Kruskal-Wallis-Test: kruskal{agricolae} and kruskalmc{pgirmess} don't yield the same results although they should do (?)

2012-08-02 Thread greatest.possible.newbie
Hi there, I am doing multiple comparisons for data that is not normally distributed. For this purpose I tried both functions kruskal{agricolae} and kruskalmc{pgirmess}. It confuses me that these functions do not yield the same results although they are doing the same thing, don't they? Can anyone

[R] multiple comparisons for GAMs

2012-08-02 Thread Bird_Girl
Hi, I have a question regarding whether it is possible to do post hoc tests on a model fit with GAM {mgcv}. My response variable is abundance (no. individuals per plot), and I have one continuous predictor (light) and one factor (height) which includes 7 levels. > mod2=gam(log_abundance~s(light

Re: [R] multiple comparisons with generalised least squares

2012-07-10 Thread Ariel
racmar wrote > > I have also been searching various forums and books to see if there are > any methods I could use and have only found people, such as yourself, > asking the same question. > I was looking into this recently, as well, and found that the problem has to do with building the model

Re: [R] multiple comparisons with generalised least squares

2012-06-05 Thread racmar
Hi Sandy, I was wondering if you ever recieved an answer regarding the use of multiple comparisons for gls models? I have also been searching various forums and books to see if there are any methods I could use and have only found people, such as yourself, asking the same question. Many thanks

[R] Multiple comparisons of lme model - interactions?

2012-02-10 Thread Fredrik Karlsson
Dear list, Please excuse my ignorance, but I'm trying to model some data using the lme package. vot is a numeric response, and condition, location and obs are all categories. This works: > anova(vot.lme <- lme(vot ~ condition * location * obs,data=mergedCodesL,random= ~1 |patient))

Re: [R] multiple comparisons in nested design (error correction)

2012-02-06 Thread José Trujillo Carmona
The last model is: AnovaModel.4 <- lmer(VR ~ trat+(1|patient:trat), data=Mesures) Sorry. El 06/02/12 13:43, José Trujillo Carmona escribió: > Dear professors and collegues > > I need to perform a analysis of dates from a nested experimental design. > > From > > "Bioestatical Analysis" of Zar >

[R] multiple comparisons in nested design

2012-02-06 Thread José Trujillo Carmona
Dear professors and collegues I need to perform a analysis of dates from a nested experimental design. From "Bioestatical Analysis" of Zar "Bimetry of Sokal" & Rohlf "Design and Analysis of Experiments" of Montgomery I have: Sum (mean(x)_i - mean(x)_T)2 / (a-1) -> var(epsilon) + n sigma2_B +

Re: [R] Multiple comparisons for coxph survival analysis model

2011-05-10 Thread jul 2-pom
Hi ExpeRts, I find this post very interesting... as I have the same problem. I found on other webpages that a solution would be to run simple comparison and then to adjust for the P-value accordingly; However, I am not very satisfied by such approach, and i would very greatful to R if a multiple c

Re: [R] multiple comparisons on a between factor

2011-04-27 Thread elgoran
: "Richard M. Heiberger" Gesendet: 27.04.2011 16:58:43 An: elgo...@web.de Betreff: Re: [R] multiple comparisons on a between factor Lisa, Please look at some of the demos in the HH package. These are built on the capabilities of the glht function in th

Re: [R] multiple comparisons on a between factor

2011-04-27 Thread Richard M. Heiberger
Lisa, Please look at some of the demos in the HH package. These are built on the capabilities of the glht function in the multcomp package. ## install.packages("HH") ## if necessary library(HH) demo("MMC.WoodEnergy-aov", package="HH") ## first demo("MMC.WoodEnergy", package="HH") ## second Ri

[R] multiple comparisons on a between factor

2011-04-27 Thread elgoran
Dear list, im facing an issue of statistical data analysis that I consider myself unable to resolve in R so i hope to get some valuable insights from you. i run an ANOVA with four factors; factor4 is an between factor (two different groups measured), the others are withins (tested a

[R] multiple comparisons with generalised least squares

2011-04-11 Thread Sandy Adriaenssens
Dear R users, I have used the following model: M1 <- gls(Nblad ~ Concentration+Season + Concentration:Season, data=DDD, weights=varIdent(form=~ 1 | Season*Concentration)) to assess the effect of Concentration and Season on nitrogen uptake by leaves (Nblad). I accounted for the difference in vari

[R] multiple comparisons after glm

2010-08-05 Thread ZAUGG Isabelle
Dear list members, I have a question concerning multiple comparisons after using glm. My response variable is days until emergence of an insect species. The explanatory variables are sex (two levels), parasitoids added (two levels) and populations (34 levels). I would like to know now which po

Re: [R] Multiple comparisons on Anova.mlm object

2010-04-16 Thread John Fox
boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf Of Bert Gunter > Sent: April-16-10 4:19 PM > To: 'Kaufman Gabriel'; r-help@r-project.org > Subject: Re: [R] Multiple comparisons on Anova.mlm object > > Gabriel: > > The post hoc comparis

Re: [R] Multiple comparisons on Anova.mlm object

2010-04-16 Thread Bert Gunter
stics -Original Message- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Kaufman Gabriel Sent: Friday, April 16, 2010 12:32 PM To: r-help@r-project.org Subject: [R] Multiple comparisons on Anova.mlm object I would like to perform multiple comparisons

[R] Multiple comparisons on Anova.mlm object

2010-04-16 Thread Kaufman Gabriel
I would like to perform multiple comparisons or post-hoc testing on the independent variable in an Anova.mlm object generated by the Anova function of the car package. I have defined a multivariate linear model and subsequently performed a repeated measures ANOVA as per the instructions in secti

Re: [R] Multiple comparisons for a two-factor ANCOVA

2010-04-09 Thread RICHARD M. HEIBERGER
On Wed, Apr 7, 2010 at 9:25 PM, Eric Scott wrote: > Thank you for your reply. The WoodEnergy example helped a lot. I > understand now that it is inappropriate to make all pairwise comparisons > with an interaction present and better to make comparisons between levels of > one factor within a co

Re: [R] Multiple comparisons for a two-factor ANCOVA

2010-04-07 Thread Eric Scott
Thank you for your reply. The WoodEnergy example helped a lot. I understand now that it is inappropriate to make all pairwise comparisons with an interaction present and better to make comparisons between levels of one factor within a constant level of the second factor. As I understand it, the s

Re: [R] Multiple comparisons for a two-factor ANCOVA

2010-03-15 Thread RICHARD M. HEIBERGER
In addtition to the example I mentioned previously, demo("MMC.WoodEnergy-aov", "HH") Please also see demo("MMC.WoodEnergy", "HH") In this example, since anova(energy.aov.4), shows that the Wood factor and Stove:Wood interaction are significant, all possible pairwise comparisons of the 12 Stove:Wo

Re: [R] Multiple comparisons for a two-factor ANCOVA

2010-03-15 Thread Eric Scott
Thanks for the example, but I'm still not sure from this example how to see the pairwise comparisons for the interaction. For example, if I have two factors, X and Y; and X has 2 levels, A and B, and Y has 3 levels, 1, 2, and 3, a TukeyHSD would give the following comparisons with p-values for eac

Re: [R] Multiple comparisons for a two-factor ANCOVA

2010-03-15 Thread RICHARD M. HEIBERGER
Please see the maiz example in ?MMC in the HH package. maiz is the last example in the help file. Keep going all the way to the end of the help file. See also the demo("MMC.WoodEnergy-aov", "HH") These examples show how to use glht in the presence of interactions and covariates. Rich

Re: [R] Multiple comparisons for a two-factor ANCOVA

2010-03-15 Thread Dieter Menne
Eric Scott-3 wrote: > > I'm trying to do an ANCOVA with two factors (clipping treatment with two > levels, and plot with 4 levels) and a covariate (stem diameter). The > response variable is fruit number. The minimal adequate model looks like > this: > > model3<-lm(fruit~clip + plot + st.dia

[R] Multiple comparisons for a two-factor ANCOVA

2010-03-15 Thread Eric Scott
I'm trying to do an ANCOVA with two factors (clipping treatment with two levels, and plot with 4 levels) and a covariate (stem diameter). The response variable is fruit number. The minimal adequate model looks like this: model3<-lm(fruit~clip + plot + st.dia + clip:plot) I'd like to get some mu

[R] Multiple comparisons with a mixed effects model

2010-03-11 Thread Sean Henderson
Hello, I have used R in the past to conduct multiple comparisons on standard linear models, but am a bit confused as to how to go about doing it with a mixed effects model. I am conducting a bioindication study using carabid beetles in which I have four treatment types (forest harvest types wi

Re: [R] multiple comparisons with non homogeneus variances

2009-11-30 Thread G. Allegri
I've forgot to cite the Games and Howell procedure, which some literature (eg in "Pairwise Multiple Comparison Procedures: A Review" [1]) referes as a good one for uneual samples and non homogeneus variance. Yet I haven't found an implementation for R... giovanni [1] http://psycnet.apa.org/journa

[R] multiple comparisons with non homogeneus variances

2009-11-30 Thread G. Allegri
This is a mixed question, between theory and practice. I have a dataset with a continous variable grouped by a 33 levels factor. After having log-tranformed my original data I can assume the normality of my data but I have two strong departures from the basic assumptions for anova and t tests: *unb

[R] Multiple comparisons for coxph survival analysis model

2009-09-26 Thread Pavel Kúr
Hello, all R-users! I am working on fitting a survival analysis model using the coxph function for Cox proportional hazards regression model. Data look like usual: == group blockdeathcensor Group1 1 4 1 Group1 1 12 1 ..

[R] multiple comparisons and generalized least squares

2009-07-02 Thread Alaerts Katrijn
Dear R users, I 'm working on a dataset consisting of 4 different dataframes with tree, leaf, fruit and seed measurements made on 300 trees, coming from 10 provenances (30 trees per provenance, 10 leaves/fruits/seeds per tree). Provenances are fixed effects (they were not randomly chosen), but

Re: [R] Multiple Comparisons for (multicomp - glht) for glm negative binomial (glm.nb)

2009-03-22 Thread Achim Zeileis
On Sun, 22 Mar 2009, lara harrup (IAH-P) wrote: Hi I have some experimental data where I have counts of the number of insects collected to different trap types rotated through 5 different location (variable -location), 4 different chemical attractants [A, B, C, D] were applied to the traps (va

[R] Multiple Comparisons for (multicomp - glht) for glm negative binomial (glm.nb)

2009-03-22 Thread lara harrup (IAH-P)
Hi I have some experimental data where I have counts of the number of insects collected to different trap types rotated through 5 different location (variable -location), 4 different chemical attractants [A, B, C, D] were applied to the traps (variable - semio) and all were trialled at two diffe

[R] multiple comparisons for MANOVA results

2008-09-20 Thread Wade Wall
Hi all, This is both a general and r specific question. I am analyzing some morphological data and have performed a MANOVA on the 5 groups with 5 measured morphological traits. The results provide me with some pairwise comparisons, but I would like to run a multiple comparison test on the result

[R] multiple comparisons

2008-03-14 Thread Stephen Cole
Hello again R help. This is a simple question perhaps(laughing as I type) with a simple answer. Is the multcomp package appropriate for using with a lme built under the nlme package. I know i can get it to work (i.e report p-values for a tukey test) but i am not unsure if this is appropriate fo

[R] Multiple comparisons and letter assignments

2008-02-04 Thread Data Analytics Corp.
Good morning, I'm trying to write a function to assign the mean separation grouping letters to the factors of an experiment. A client wants this so I thought I'd write my own function for future use. But I'm having trouble doing it because I don't understand the logic of the assignment. As

Re: [R] multiple comparisons/tukey kramer

2007-11-26 Thread Tyler Smith
On 2007-11-23, hadley wickham <[EMAIL PROTECTED]> wrote: >> >> What I need is a reference to the tests implemented in glht, so I can >> decide which one is appropriate for my data. Sequen, Changepoint et >> al. may be common terms in some fields, but not in the references I'm >> working from. > > H

Re: [R] multiple comparisons/tukey kramer

2007-11-23 Thread hadley wickham
> However, I don't know what exactly glht does, and the help file is > extremely terse. It offers the following options (in contrMat()): > > contrMat(n, type=c("Dunnett", "Tukey", "Sequen", "AVE", > "Changepoint", "Williams", "Marcus", > "McDermo

Re: [R] multiple comparisons/tukey kramer

2007-11-23 Thread Tyler Smith
Thank you for your response. I think you have misunderstood what I'm asking, though. On 2007-11-23, Emmanuel Charpentier <[EMAIL PROTECTED]> wrote: > > - Tukey HSD will enable you to test the p(p-1)/2 pair differences one > can create with p groups ; > - Dunnett's procedure is made to compare (p-

Re: [R] multiple comparisons/tukey kramer

2007-11-23 Thread Emmanuel Charpentier
Tyler Smith a écrit : > Hi, > > I'm trying to make sense of the options for multiple comparisons > options in R. I've found the following options: [ Snip ... ] > As I understand it, there is no universal consensus as to which test > is best. There is no such thing. Each of the procedures is aim

[R] multiple comparisons/tukey kramer

2007-11-23 Thread Tyler Smith
Hi, I'm trying to make sense of the options for multiple comparisons options in R. I've found the following options: pairwise.t.test, which provides standard t-tests, with options for choosing an appropriate correction for multiple comparisons TukeyHSD, which provides the usual Tukey test glht(

[R] Multiple comparisons; rank-based anova

2007-09-25 Thread Mark Difford
Dear List-Members, Is the application of multiple comparison procedures (using the multcomp package) to the output from a rank-based ANOVA straightforward, or do I need to take heed ? That is, is it as simple as: glht( aov(rank(NH4) ~ Site, data=mydat), linfct=mcp(Site="Tukey") ) Thanks in adv