similar to: Longitudinal analysis: contrasting time points

Hi, I am trying to model a score over time. This score shows a ceiling effect. I was willing to use a longitudinal tobit model, such as the one described by Twisk et al. (Twisk_Longitudinal tobit regression: A new approach to analyze outcome variables with floor or ceiling effects_JCE_2009) but it is programmed for STATA. Has anyone used such models in R? Any other idea? David Biau.

Hi everyone I have the following problem: My dataframe has 3 variables: ID, Year and and an outcome variable. The dataframe contains repeated measurements because the subjects filled out a questionnaire every year. The time span covers 2 years. Now I want to check if there is a significant change in the outcome over the 2 years with a paired wilcox.test. The problem: Not every subject

Hey list and possible Arne... I try to get traffic shaping working on my firewall but getting cunfused with settings, but first my current setup: tcclasses file: #INTERFACE MARK RATE CEIL PRIORITY OPTIONS $EXT_IF 10 64kbit full 1 tcp-ack,tos-minimize-delay $EXT_IF 20 full/3 full/2 2 default $EXT_IF 30

Hi all, this is a long time since my last post to this list and I have got a small question... (ofcource :) I'm going to introduce citrix into our office (two citrix XPa servers which are load balanced). According to the Citrix XPa docs it is not a good idea to use one of this servers as a PDC/BDC, I can imagine that (we wouldn`t want to give NT to much responsebilities). so my question

Hello, I just wanted to save a graphic in the pdf-format. But id failed: Fehler: Invalid font type Zus?tzlich: Warning messages: 1: font family not found in PostScript font database 2: font family not found in PostScript font database I use R 2.6.0 with all packages updated recently. Any idea? Thank you very much! Best, Denis __ Denis Aydin mailto:Denis.Aydin at stud.unibas.ch Montag, 22.

Dear R-helpers I have a question related to logistic GAM models. Consider the following example: # Load package library(mgcv) # Simulation of dataset n <- 1000 set.seed(0) age <- rnorm(n, 50, 10) blood.pressure <- rnorm(n, 120, 15) cholesterol <- rnorm(n, 200, 25) sex <- factor(sample(c('female','male'), n,TRUE)) L <-

Dear all, I am trying to migrate one of our systems to dovecot. We were using uw-imapd in black-box-mode before. Since the home-directory of a user is not unique per definition on our systems, we have kind of a different setup. As an example: I got a user, let's say user1. It's home directory is /local/web/websites/5850844095/www. This directory has the following permissions: # ls -la

Hi, I try to make a histogram from a variable that contains the number of shoots from about 1000 individuals from a specific plant species (the range is 1-110). Those numbers are highly skewed to the right. My question is: how can I make my own classes with the lattice "histogram"? I tried it with "breaks=c(0,5,10,15,20,25,110)" but my "25-110"-class is presented

Hi R help list I'm simulating logistic regression data with a specified odds ratio (beta) and have a problem/unexpected behaviour that occurs. The datasets includes a lognormal exposure and diseased and healthy subjects. Here is my loop: ors <- vector() for(i in 1:200){ # First, I create a vector with a lognormally distributed exposure: n <- 10000 # number of study subjects

I find the file metaconfig.yaml very useful and I use it for setting the title and order of files. However, I can''t find a way to change the order of a directory. Consider the file layout: index.page dir/sub1.page I want to choose whether the order in the menu is [index,dir] or [dir, index]. I tried with: dir/: orderInfo: 1 or dir: orderInfo: 1

Hi I have a question regarding an output of a binomial lmer-model. The model is as follows: lmer(y~diet * day * female + (day|female),family=binomial) The corresponding output is: Generalized linear mixed model fit by the Laplace approximation Formula: y ~ diet * day * female + (day | female) AIC BIC logLik deviance 1084 1136 -531.1 1062 Random effects: Groups Name Variance

If I got this to work, do you think we could/should check in rspec_autotest into rspec? I''ve updated rspec_autotest abit, so let me know if you''d like the modified code. Scott

Dear all I want to run a simple multiple linear regression model, say: mod <- lm(y~x1+x2+x3+x4) I have programmed a custom algorithm to calculate the p-values, because there is clustering present. I ordered the variables according to their p-value and want to stepwise eliminate the variables with the highest p-values. My question: How can I use "update" when I have only the

I've gotten 4 e-mails from this list today from people who were sending out this virus. It appears to be spreading rather quickly. I would urge all of you to update your virus software and get rid of this bug quickly. Thanks, James Simons

Hi all, I a semi-beginner with R and I am working with the plm package to examine a longitudinal dataset. Each individual in this dataset has a longitudinal weight for the probability that he or she remains in the sample. Unfortunately, I have not found an argument to use weights in the plm function? I tried ?weights=? like in standard lm or in nlme or lm4 but it does not work. I asked the

Hi all: I have a question about the sample size calculation. It's a pilot study,which includes 2 groups(low,high),3 time point(3,6,9 monthes).Each person has 3 results which according to the 3 time points.So it's a longitudinal study. I want to calculate the minimum sample size from the pilot study, but can't find the solution since the data is highly skewed and it's a

Dear List,   I have some longitudinal data, each patient was followed at times 0, 12, 16, 24 weeks and measure severity of a illness (0-worse, 1-same, 2-better). So, longitudinal response is categorical.  I was wondering whether lmer in R can fit a model for this type of data. If so, how we code? Or any other function in R that can fit this type of longitudinal data? Any suggestion would be

Dear R-Users! Is there a possibility in R to do analyze longitudinal survey data (repeated measures in a survey)? I know that for longitudinal data I can use lme() to incorporate the correlation structure within individual and I know that there is the package survey for analyzing survey data. How can I combine both? I am trying to calculate design-based estimates. However, if I use svyglm() from

i am studying Longitudinal Data Analysis and want to carry it with R.anyone knows any materials about Longitudinal Data Analysis with R in the internet which i can download? thank you.

Hi, does anyone out there have a recommendation for multilevel / random effects and longitudinal analysis? My dream book would be something that's both accessible to a non-statistician but rigorous (because I seem to be slowly turning into a statistician) and ideally would use R. Peter