similar to: var/cov matrix for a quantile regression model

Dear all, I found a problem with 'lme4'. Basically, once you load the package 'aod' (Analysis of Overdispersed Data), the functions 'lmer' and 'glmer' don't work anymore: library(lme4) (fm1 <- lmer(Reaction ~ Days + (Days|Subject), sleepstudy)) (gm1 <- glmer(cbind(incidence, size - incidence) ~ period + (1 | herd), family = binomial, data

Dear all, I'm trying to estimate the parameters of a special case of a poisson model, where the specified equation has an integral and several fixed parameters. I think that the MLE command in STATS4 package could be a good choice, but it's a little complicated. I've got some problems with the offset and I don't understand some of the functions. Do you know where can I find some

Dear R users, I use the glm() function to fit a generalized linear model with gamma distribution function and log link. I have read in the help page that the default method used by R is "glm.fit" (iteratively reweighted least squares, IWLS). Is it possible to use maximum likelihood method? Thanks Silvia Narduzzi Dipartimento di Epidemiologia ASL RM E Via di S. Costanza, 53 00198

Dear all, I have a very basic question: how does the logLik function work for poisson models? Example: I simulate 20 observations from a Poisson distribution with mean 800. y <- rpois(20,800) model <- glm(y ~ 1, family=poisson()) logLik(model) I would like to know what's the exact formula the function logLik uses. I looked at ?extractAIC but I cannot sort it out. Can you please

Hello, I'm trying to save a graph as a .ps file to include it in a LaTex presentation, but R replies: Error: Invalid font type In addition: Warning messages: 1: font family not found in PostScript font database 2: font family not found in PostScript font database If I load the package grDevices and type "postscript()" then I can save it, but it creates also a text file saying:

Dear Wolfgang Viechtbauer and R users, I have few questions regarding the development of the package 'metafor. As you suggested , I post to the R-help mailing list. I read you're planning an extension of this method to the multivariate case. I think it would be a useful tool. I'm currently performing some analyses with R on multiple outcomes, using the Stata command mvmeta to get

Hi the list, I have a problem of memory space while running step() function: Error: cannot allocate vector of size 50.9 Mb I've tried with: > memory.size(max = FALSE) [1] 803.4714 #which should be the amount of memory currently in use > memory.limit(size = NA) [1] 1015.480 #which should be the memory size > memory.size(max = TRUE) [1] 997.75 #which should be the

Dear all, I've tried to solve the Es. 12, cap 4 of "Introduction to GLM" by Annette Dobson. It's about the relationship between survival time of leukemia patients and blood cell count. I tried to fit a model with exponential distribution, first by glm (family gamma and then dispersion parameter fixed to 1) and then with survreg. They gave me the same point estimates but the

Hello, I have compared the potentials of R and Stata about GLMM, analysing the dataset 'ohio' in the package 'faraway' (the same dataset is analysed with GEE in the book 'Extending the linear model with R' by Julian Faraway). Basically, I've tried the 2 commands 'glmmPQL' and 'glmer' of R and the command 'xtmelogit' of Stata. If I'm not

Dear fellows, I'm trying to extract the AIC statistic from a GLM model with quasipoisson link. The formula I'm referring to is AIC = -2(maximum loglik) + 2df * phi with phi the overdispersion parameter, as reported in: Peng et al., Model choice in time series studies os air pollution and mortality. J R Stat Soc A, 2006; 162: pag 190. Unfortunately, the function logLik

Dear Gustaf, I wish you a happy new year! I am a PhD Staff at LSHTM and I have been trying to use WHO anthro macros in R with the file you posted on internet but when I double check the WHZ, HAZ, WAZ output with output from ENA or STATA, it differs slightly. Do you have any idea why that might be the case? Many thanks Severine

Dear R-listers, I am writing a function that will generate a simple plot for the user . The size of the window (that contains the plot) may not be what the user wants. Supposing the user adjusts the window to a size of her/his choice, I would like to be able to save the new window size and specify the plot to be of this new window size when the user calls my function again. My question is

Dear R users, I'm trying to specify a generalized linear mixed model in R, basically a Poisson model to describe monthly series of counts in different regions. My aim is to fit subject-specific curves, modelling a non-linear trend for each region through random effects for linear splines components (see Durban et al, Stat Med 2005, or " Semiparametric regression" by Ruppert et al,

Win2k, R1.6.2. I've been using Splus 6.1 and wanted to try the same regression analysis in R. Using "names( blah.lm )" in R yields [1] "coefficients" "residuals" "effects" "rank" [5] "fitted.values" "assign" "qr" "df.residual" [9] "xlevels"

Dear list, I will shortly have some data that contains numeric dates in the Persian / Jalali calendar format, which I would like to convert to gregorian. At the moment there doesn't seem to be a function for this in R, but it would be great if someone could come up with same - I would attempt it but the algorithm is very complex and this is also way beyond my fairly rudimentary knowledge of

Hello, Is there a way to get the Var-Cov matrix from the LMER function? Thanks [[alternative HTML version deleted]]

Dear colleagues, I'm an epidemiologist with no background in programming and just started using R a few weeks ago. I am working on the epidemiology of African sleeping sickness, and am trying to use R to perform a Monte Carlo Markov Chain analysis to estimate three unknown parameters within a model of African sleeping sickness case detection that is mainly informed by actual field programme

Dear R users, I included 2 internal functions in the package 'dlnm', called 'mkbasis' and 'mklagbasis'. Despite they are not meant to be called by the users, I included them in the namespace in order to make them available, keeping the process more transparent and giving the opportunity to change or improve them. I included an help page 'dlnm-internal.Rd' to

Dear R users, I included 2 internal functions in the package 'dlnm', called 'mkbasis' and 'mklagbasis'. Despite they are not meant to be called by the users, I included them in the namespace in order to make them available, keeping the process more transparent and giving the opportunity to change or improve them. I included an help page 'dlnm-internal.Rd' to

Dear R Community, I am pleased to announce the release of a new package called 'dlnm', now available on CRAN (version 0.2.1). The package dlnm provides some facilities to run distributed lag models (DLM's) and their non-linear extension (DLNM's), a modelling framework to describe simultaneously non-linear and delayed effects between predictors and an outcome in time-series