similar to: Logistic regression: At times correlation matrix of coefficients gets messed up

Hi, I'm using geeglm function to account for the repeated measure. fit1<- geeglm( binary.outcome ~ age + race + gender + fever.yes.no, data=mydata, id=ID, family=binomial, corstr="exchangeable") summary(fit1)$coef gives too large estimates and standard deviation: Estimate Std.err Wald Pr(>|W|) (Intercept) 3.07e+16

I recently posted a question concerning an inconsistency of expand.grid in defining the reference level of the factors. > > expand.grid(x = c("b", "a"), y = c(1, 2))$x > [1] b a b a > Levels: b a # reference level is b > > expand.grid(x = c("b", "a"))$x > [1] b a > Levels: a b # reference level is a Thank you

Dear R list, I am reading in text file data prepared in Access database by someone. One of the field contains timestamp data, how can I separate the timestamp data into two varaibles: date and time. Can I specify the field is in timestamp format when I first reading in ? My reading in data are as below: 449 LWT 22/10/2003 15:43:00 441 143 449 LWT 17/11/2003 15:25:00 421 169 449 LWT

Hi, I would like to see if a matching variable is an effect-modifier in a conditional logistic regression. Naturally, the matching variable can't enter directly in the model but as an interaction with terms that are in. However, I have problems in formulating the correct model the term that's already in the model is a factor. I am using treatment contrasts and the problem is that if I

Hello all I have what seems like a simple question but have not been able to find an answer on the forum. I'm trying to define a function which involves regression models and a large number of covariates. I would like the function to accept any number of covariates and, ideally, I would like to be able to enter the covariates in a group (e.g. as a list) rather than individually. Is there any

List, I'm working on fitting a logistic model for a well known dataset (which is given below in case anyone wants to try to reproduce). I used both R and SAS to fit the model and have some differences in the parameter estimates. I'm wondering if R calculates the ML estimates differently. I'm making NO accusations as to which program is "right or wrong". That is not the

Hi. guys, I am trying to write my own Stochastic Gradient Ascent for logistic regression in R. But it seems that I am having convergence problem. Am I doing anything wrong, or just the data is off? Here is my code in R - lbw <- read.table("http://www.biostat.jhsph.edu/~ririzarr/Teaching/754/lbw.dat" , header=TRUE) attach(lbw) lbw[1:2,] low age lwt race smoke ptl ht ui ftv

Dear R users, Thanks in advance. I am Deb, Statistician at NSW Department of Commerce, Sydney. I am using R 2.9.1 on Windows XP. This has reference to the package “MCMCpack”. My objective is to select a better model using various alternatives. I have provided here an example code from MCMCpack.pdf. The matrix of Bayes Factors is: model1 model2 model3 model1 1.000 14.08

Hi folks, I have five imputed data sets and would like to apply the same recoding routines to each. I could do this sort of thing pretty easily in Stata using MIM, but I've decided to go cold turkey on other stats packages as a incentive for learning more about R. Most of the recoding is for nominal variables, like race, religion, urbanicity, and the like. So, for example, to recode race

Dear friends, In R, the help of "bic.glm" tells the difference between postmean(the posterior mean of each coefficient from model averaging) and condpostmean(the posterior mean of each coefficient conditional on the variable being included in the model), But it's still unclear about the results explanations, and the artile of Rnews in 2005 on BMA still don't give more detail on

Hello, I am looking at the job satisfaction data below, from a problem in Agresti's book, and I am not sure where the degrees of freedom come from. The way I am fitting a binomial model, I have 168 observations, so in my understanding that should also be the number of fitted parameters in the saturated model. Since I have one intercept parameter, I was thinking to get 167 df for the Null

Hi. I've managed to make a *very* simple wrapper around the xts library for R into OCaml. (Need to be downloaded from CRAN for OCaml users, but I expect other wrapping to be fairly similar...). The good, good, good thing (from my humble point of view) is that all loading is done statically: Loading the R interpreter is done statically. Loading the xts library is done statically... etc...

Happy New Year to all, I am using RW0631 and WIN98. 1. The command DATA only works for the base library. 2. The following code on page 312 of Venables and Ripley 1997 sitka.lme <- lme(size~treat*ordered(Time),random=~1,cluster=~tree,data=Sitka, serial.structure="ar1.continuous",serial.covariate=~Time) produced the following error message Error in lme(size ~ treat *

This post is to announce the 0.2 release of OCaml-R. OCaml-R is a binding embedding the R interpreter into Objective Caml code. Home page: http://home.gna.org/ocaml-r/ Download page: http://download.gna.org/ocaml-r/ Deb packages: http://yziquel.homelinux.org/debian/pool/main/o/ocaml-r/ Tutorial: http://home.gna.org/ocaml-r/gettingstarted.en.html OCamlDoc API:

Hi, I'm new to R and using it for Cox survival analysis. Thanks to this great forum I learned how to compute the HR with its confidence interval. My question would be: Is there any way to get the p-value for a hazard ratio in addition to the confidence interval? Thanks, Thierry -- Thierry Panje Visiting Student Researcher Department of Psychology Stanford

Fellow R Users: I'm not extremely familiar with lda or R programming, but a recent editorial review of a manuscript submission has prompted a crash cousre. I am on this forum hoping I could solicit some much needed advice for deriving a classification equation. I have used three basic measurements in lda to predict two groups: male and female. I have a working model, low Wilk's lambda,

The birth weight example from ?stepAIC in package MASS runs well as indeed it should. However when I change stepAIC() calls to step() calls I get warning messages that I don't understand, although the output is similar. Warning messages: 1: In model.response(m, "numeric") : using type="numeric" with a factor response will be ignored (and three more the same.) Checked

Hi everyone, I have some question about the Xenopsd. I’ve read the wiki document but cannot understand where to use it, Is this different with XAPI ? What’s the main work for? Can anyone describe it more clearly about it? Thanks a lot!! _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users

Hey guys, I was playing around with the command "rake db_schema_dump" and kept getting this error "no such file or directory - /tmp/mysql.sock". I tried looking around to find this mysql.sock file; but no luck so far. Question: What is mysql.sock file? (how does it get created and how does it get used) I installed a MySQL DB and could not find this file. Could someone help

The following series of patches fill in most of the gaps in the OCaml bindings to libxl, to make them useful for clients such as xapi/xenopsd (from XCP). There are a number of bugfixes to the existing bindings as well. I have an experimental version of xenopsd that successfully uses the new bindings. An earlier version of the first half of the series was submitted to the last by Ian Campbell on