similar to: Latent trait models

Hello, I am trying to fit a nlme (non linear mixed effect). I am using the SelfStart function SSlogis. However the data in my hand contains few observations per subject (4 or less), so the nlsList doesn't work... In this case I should fixe initial parameter estimates. I remark that values of initial estimates have a greater effect on the model fit (i.e. loglikelihood, AIC and also on

Hi everyone, Does the selfstart function SSlogis of the "nlme" library allows the introduction of time varying covariates ? For example how can I interpret the xmid parameter (reperesenting the age at which we reach the half of the asymptote) if I want to explain it by a some time varying covariate? Thanks in adavance, Abderrahim Abderrahim Oulhaj, Phd in Statistics Oxford

Dear All, I wonder if there is an efficient way to fit the generalized linear mixed model for multivariate outcomes. More specifically, Suppose that for a given subject i and at a given time j we observe a multivariate outcome Yij = (Y_ij1, Y_ij2, ..., Y_ijK). where Y_ijk is a binomial(n_ijk, p_ijk). One way to jointly model the data is to use the following specification: g(p_ijk) =

Dear All, I wonder if there is a way to fit a generalized linear mixed models (for repeated binomial data) via a direct Maximum Likelihood Approach. The "glmm" in the "repeated" package (Lindsey), the "glmmPQL" in the "MASS" package (Ripley) and "glmmGIBBS" (Myle and Calyton) are not using the full maximum likelihood as I understand. The

Dear R-users, I'd like to announce the release of my new package "ltm" (available from CRAN), for fitting Latent Trait Models (including the Rasch model) under the Item Response Theory approach. The latent trait model is the analogous of the factor analysis model for Bernoulli response data. "ltm" fits the linear one- and two-factor models but also allows for

Dear R-users, I'd like to announce the release of my new package "ltm" (available from CRAN), for fitting Latent Trait Models (including the Rasch model) under the Item Response Theory approach. The latent trait model is the analogous of the factor analysis model for Bernoulli response data. "ltm" fits the linear one- and two-factor models but also allows for

Dear All, I have the following error message when I fitted lmer to a binary data with the "AGQ" option: Error in family$mu.eta(eta) : NAs are not allowed in subscripted assignments In addition: Warning message: IRLS iterations for PQL did not converge Any help? Thanks in advance, Abderrahim [[alternative HTML version deleted]]

Hello, I got an error message saying Error in lognet(x, is.sparse, ix, jx, y, weights, offset, alpha, nobs, : NA/NaN/Inf in foreign function call (arg 5) when I try to analysis a binary trait using glmnet(R) by running the following code library(glmnet) Xori <- read.table("c:\\SNP.txt", sep='\t'); Yori <- read.table("c:\\Trait.txt", sep=',');

Is there a package that will allow me to fit Brownian motion and Ornstein?Uhlenbeck models of evolution for discrete traits? I know that geiger and ouch have commands for fitting these models for continuous traits, but these aren't suitable for discrete trait evolution, correct? -- View this message in context:

Hi All: This may turn out to be very simply, but I can't seem to add the name of the school to a chart. The loop I created is below that subsets a dataframe and creates a chart for each school based on certain variables. As it stands now, they title includes the school's ID number. Instead, I want to replace this with the school's actual name, which is stored in a variable called

Hi All, I finally signed up for the list after years of using Samba successfully - a testament to the quality of Samba. Yet now I have a problem with the point-and-print functionality. I am able to authenticate against my server (Solaris 8, Samba 3.0.7, OpenLDAP 2.1.25) as user 'chuck' in my LDAP directory and browse the shares, but when I right-click on the printer and select

Ein eingebundener Text mit undefiniertem Zeichensatz wurde abgetrennt. Name: nicht verf?gbar URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20130611/09dcb017/attachment.pl>

Ok.. Just for the record, I STAND CORRECTED! The problem does appear to be NT.. The thing that irritated me was that nobody was interested in giving any backup data! Everyone just wanted to blindly admit that it must be NT. Ok.. Enuf bitching.. On to the better stuff... Anyway, David Mansfield and I are trying to narrow down the machine configurations where this happens.. Currently, we've

Dear R help list, I am desperately looking for any reference explaining by examples how to write R codes in order to fit the parameters of a given model using maximum likelihood or any other criteria function. I know the general structure: First write a code for the maximum likelihood function and afterwards write a code to maximize it using optim and then invert the Hessian to get the

Ernie, Thanks for the great info.. Based on what you were seeing, would you suspect that part of the problem is with the combination of NT and the 3com card (3c595)? Currently, we are ONLY seeing this under NT Workstation (not server) and almost all of our machines have this same 3com 3c595 card (only if using 100BaseT).. -- Rick -----Original Message----- From: Ernie Oporto

Dear all, I am looking for an R package that fits multivariate gaussian or non-gaussian longitudinal outcomes. I am especially interested to non-gaussian outcomes since the outcomes I've got are discrete (some are binomial and some are count data). Many thanks in advance, Abderrahim [[alternative HTML version deleted]]

Dear all, at the Division of Clinical Pharmacology at the University of Cape Town (South Africa) we are looking for highly motivated science/engineering PhD graduates to join our pharmacometrics group as a post-doctoral fellow. Pharmacometrics is an emerging discipline that applies mathematical modelling and simulation to pharmacology, aiding the interpretation of data from clinical trials,

Hai, Can anyone help me with some literature (R related) about latent models? Thanx, Wilfred

Dear all, Our pharmacometrics group is looking for bright and motivated candidates to join our modelling team within the Division of Clinical Pharmacology at the University of Cape Town. Our group has established PK/PD modelling expertise in the disease areas of tuberculosis, HIV, and malaria. It is active internationally and enjoys on-going collaborations and exchange programs with some of the

Dear all, We are looking for bright and motivated candidates to join our pharmacometric modelling team at the University of Cape Town. Pharmacometrics is an emerging discipline that uses mathematical and statistical tools to quantify drug, disease, and trial information to aid efficient drug development and/or regulatory decisions. It designs and applies mathematical models to describe the