similar to: lmer, p-values and all that

Hello. Douglas Bates has explained in a previous posting to R why he does not output residual degrees of freedom, F values and probabilities in the mixed model (lmer) function: because the usual degrees of freedom (obs - fixed df -1) are not exact and are really only upper bounds. I am interpreting what he said but I am not a professional statistician, so I might be getting this wrong... Does

(This time with the r-help in the recipients...) Be careful when mixing lme4 and lmerTest together -- lmerTest extends and changes the behavior of various lme4 functions. >From the help page for lme4-anova (?lme4::anova.merMod) > ?anova?: returns the sequential decomposition of the contributions > of fixed-effects terms or, for multiple arguments, model >

From a quick look at the paper in the SAS proceedings, the simulations seem limited to nested designs. The major problems are with repeated measures designs where the error structure is not compound symmetric, which lme4 does not at present handle (unless I have missed something). Such imbalance as was investigated was not a serious issue, at least for the Kenward and Roger degree of freedom

Please reread my point #1: the tests of the (individual) coefficients in the model summary are not the same as the ANOVA tests. There is a certain correspondence between the two (i.e. between the coding of your categorical variables and the type of sum of squares; and for a model with a single predictor, F=t^2), but they are not the same in general. The t-test in the model coefficients is simply

[Please use the subject line!] In the help page for summary.lm, the "Value" section says that the returned object has a component called "fstatistic", which has the F-statistic and the associated numerator and denominator degrees of freedom. You can get the p-value by something like: fstat <- summary(speciallinearmodel)$fstatistic pval <- pf(fstat[1], fstat[2],

Dear All, I used lmer for data with non-normally distributed error and both fixed and random effects. I tried to calculate a "Type III" sums of squares result, by I conducting likelihood ratio tests of the full model against a model reduced by one variable at a time (for each variable separately). These tests gave appropriate degrees of freedom for each of the two fixed effects, but

Dear list members, I am new to R and to the R-help list. I am trying to perform a mixed-model analysis using the lmer() function. I have a problem with the output anova table when using the anova() function on the lmer output object: I only get the numerator d.f., the sum of squares and the mean squares, but not the denominator d.f., F statistics and P values. Below is a sample output, following

Dear lmer-ers, My thanks for all of you who are sharing your trials and tribulations publicly. I was hoping to elicit some feedback on my thoughts on denominator degrees of freedom for F ratios in mixed models. These thoughts and practices result from my reading of previous postings by Doug Bates and others. - I start by assuming that the appropriate denominator degrees lies between n

Thanks to Rolph Turner and Jason Turner ... I guess I was too excited about getting back on the list after an absense of several years ... I'll be a little more thoughtful about the problem before posting next time, and a little less trigger-happy with the "Send" e-mail button. Never-the-less, much appreciated. - Mohamed -----Original Message----- From: Rolf Turner

Hi, this is not a new doubt, but is a doubt that I cant find a good response. Look this output: > m.lme <- lme(Yvar~Xvar,random=~1|Plot1/Plot2/Plot3) > anova(m.lme) numDF denDF F-value p-value (Intercept) 1 860 210.2457 <.0001 Xvar 1 2 1.2352 0.3821 > summary(m.lme) Linear mixed-effects model fit by REML Data: NULL AIC BIC

When I do lmer models I only get Estimate, Standard Error and t value in the output for the fixed effects. Is there a way I get degrees of freedom and p values as well? I'm a very new to R, so sorry if this a stupid question. Thank you - Mike Mike Ford Centre for Speech and Language Department of Experimental Psychology Downing Street Cambridge CB2 3EB Tel: +44 (0) 1223 766559 Fax: +44

tl;dr anova.lme() claims to provide sums of squares, but it doesn't. And some names are misspelled in ?lme. I can submit all this stuff as a bug report if that's preferred. ?anova.lme says: When only one fitted model object is present, a data frame with the sums of squares, numerator degrees of freedom, denominator degrees of freedom, F-values, and P-values The output of fm1

Hi, 1/ I wonder why a anova.lme on a single lme object does not print the sum of squares (as expected from the help: "a data frame with the sums of squares, numerator degrees of freedom, denominator degrees of freedom, F-values, and P-values"). Example: > fm2 <- lme(distance ~ age + Sex, data = Orthodont, random = ~ 1) > anova(fm2) numDF denDF F-value p-value

Dear R users, I've notice that there are two ways to conduct a binomial GLM with binomial counts using R. The first way is outlined by Michael Crawley in his "Statistical Computing book" (p 520-521): >dose=c(1,3,10,30,100) >dead = c(2,10,40,96,98) >batch=c(100,90,98,100,100) >response = cbind(dead,batch-dead) >model1=glm(y~log(dose),binomial)

Hello,   I'd like to compare the predictive power of two independent simple regression models, which relate to data sets with different numbers of points (n1 and n2). I think I could use a F-test to compare both residual variances, but I don't know whether it's a good idea or not. To my opinion, the numbers of degrees of freedom for the F-test would be respectively the number of

>>>>> Ben Bolker >>>>> on Thu, 17 Jan 2019 12:32:20 -0500 writes: > tl;dr anova.lme() claims to provide sums of squares, but it doesn't. And > some names are misspelled in ?lme. I can submit all this stuff as a bug > report if that's preferred. > ?anova.lme says: > When only one fitted model object is present, a data

Hi, Is there a way to provide starting values for the fixed effects in lmer()? I'd like to fit the following model, which requires starting values in the glm.fit() part of the code: lmer(dbh.sum ~ Treatment + (1|Site), nets, gaussian("log"), subset=Treatment!="sforest" & iocTreat!="forest") I tried tinkering with the code but I couldn't figure out the

Dear R user I have 2 problems with lmer. The statistical consultance service of my university has recomended to me to expose those problems here. Sorry for this quite long message. Your help will be greatly appreciated... Gilles San Martin 1) anova() I fit a first model : model1 <- lmer(eclw~1 + density + landsc + temp + landsc:temp + (1|region) + (1|region:pop) + (1|region:pop:family),

Hello all. I was wondering if there is any way to adjust the denominator degrees of freedom in lme(). It seems to me that there is only one method that can be used. As has been pointed out previously on the list, the denominator degrees of freedom given by lme() do not match those given by SAS Proc Mixed or HLM5. Proc Mixed, for example, offers five different options for computing the

Dear all, I am starting to use the lme package (and plan to teach a course based on it next semester...). To understand what lme is doing precisely, I used balanced datasets described in Pinheiro and Bates and tried to compare the lme outputs to that of aov. Here is what I obtained: > data(Machines) > summary(aov(score~Machine+Error(Worker/Machine),data=Machines)) Error: Worker