search for: egsingle

Dear List: I was able to run the following in nlme successfully, but the same model and code (same dataset) failed to run in lme4 and gave me the error message below. Any thoughts? lme(math~year, data=egsingle, random=~year|schoolid/childid) Error in lme(formula = math ~ year, data = egsingle, random = structure(list( : Unable to invert singular factor of downdated X'X Harold [[alternative HTML version deleted]]

...stimates from both models are the same. fm1 <- lmer(Reaction ~ Days + (Days|Subject), sleepstudy, method='ML') fm2 <- lme(Reaction ~ Days, random=~Days|Subject, sleepstudy, method='ML') Now, assume you want to extend this to include additional levels of random variation. The egsingle data set in the mlmRev package has repeated measures on students and those students are nested in schools. We can fit a model with random intercepts and slopes for students and students within schools. The first model is fit using lme and the second is fit using lmer. fm3 <- lme(math ~ year, ra...

Paul: I may have found the issue (which is similar to your conclusion). I checked using egsingle in the mlmRev package as these individuals are strictly nested in this case: library(mlmRev) library(nlme) fm1 <- lme(math ~ year, random=~1|schoolid/childid, egsingle) fm2 <- lmer(math ~ year +(1|schoolid:childid) + (1|schoolid), egsingle) Checking the summary of both models, the output i...

...and, but it isn't working. For example, the code would perform something similar to: hist(paste("grade", "4", "$math",sep="")) which doesn't work. The code below is what I hope will ultimately be the working loop. grade.list<-as.vector(unique(egsingle$grade)) for(grade.number in grade.list){ pdf(paste("grade",grade.number,".pdf",sep="")) hist(paste("grade",grade.number,"$math",sep="")) dev.off()} I'm a little confused on how to get this work properly. Any thoughts are much appreci...

Hi everyone, I would like to ask a question regarding to the data used to fit the mixed model. I wonder that, for the response variable data used to fit the mixed model (either via "spm" or "lme"), we must have several observations per subject (i.e. Yij, i = 1,..,M, j = 1,.., ni) or it can be just one observation per subject (i.e. Yi, i = 1,...,M). Since we have to

Dear ListeRs, I am trying to fit a heteroscedastic multilevel model using lmer{lme4- package). Take, for instance, the (fictive) model below. lmer(test.result ~ homework + Sex -1 + (1 | School)) Suppose that I suspect the error terms in the predicted values to differ between men and women (so, on the first level). In order to model this, I want the 'Sex'-variable to be random on

Hello, I am looking for a way to obtain standard errors for emprirical Bayes estimates of a model fitted with lmer (like the ones plotted on page 14 of the document available at http://www.eric.ed.gov/ERICDocs/data/ericdocs2/content_storage_01/0000000b/80/2b/b3/94.pdf). Harold Doran mentioned (http://tolstoy.newcastle.edu.au/~rking/R/help/05/08/10638.html) that the posterior modes' variances