Displaying 20 results from an estimated 200 matches similar to: "pbc data"
2008 Nov 24
1
Discrepancy in the PBC data set
The data set in R is wrong. I've found mistakes on 2 lines in a quick look.
I don't know if the data is incorrect in the Appendix of Fleming and
Harrington as well (someone seems to have borrowed my copy), which is where the
data set appears to have been taken from, given all the "-9" codes in it. (Note,
Tom Fleming originally got the data from me, so I'm fairly
2008 Nov 21
1
Discrepancy in the regression coefficients for Cox regression - PBC data set
Hi,
When I run the following Cox proportional hazards model on the Mayo clinic's
PBC data set (given in the "survival" package), the regression coefficients
do not agree with the results presented in Table 4.6.3 (p. 195) of Fleming &
Harrington's book.
library(survival)
data(pbc)
ans.cox <- coxph(Surv(time, status) ~ log(bili) + log(alb) + age +
log(protime) +
2003 Aug 04
1
coxph and frailty
Hi:
I have a few clarification questions about the elements returned by
the coxph function used in conjuction with a frailty term.
I create the following group variable:
group <- NULL
group[id<50] <- 1
group[id>=50 & id<100] <- 2
group[id>=100 & id<150] <- 3
group[id>=150 & id<200] <- 4
group[id>=200 & id<250] <- 5
group[id>=250
2006 Sep 03
2
Running cox models
Hi,
I'm reading van Belle et al "Biostatistics" and trying to run a cox test using
a dataset from:
http://faculty.washington.edu/~heagerty/Books/Biostatistics/chapter16.html
(Primary Biliary Cirrhosis data link at top of the page),
I'm using the following code:
--------------- start of code
library(survival)
liver <-
2011 Apr 20
2
survexp with weights
Hello,
I probably have a syntax error in trying to generate an expected
survival curve from a weighted cox model, but I can't see it. I used
the help sample code to generate a weighted model, with the addition
of a "weights=albumin" argument (I only chose albumin because it had
no missing values, not because of any real relevance). Below are my
code with the resulting error
2008 Mar 02
0
new to latex to pdf
Dear All,
I'm trying to teach myself latex along with the latex function in Hmisc
and have hit a roadblock that I can't seem to get around. I'd greatly
appreciate any pointers.
I'm running R 2.6.0 on Windows XP and have Miktex 2.7 installed.
I've reproduced the code below, taken from Frank Harrell's latexsummary
introduction. My question relates to getting a pdf
2007 Nov 24
1
Hmisc: can not reproduce figure 4 of Statistical Tables and Plots using S and LATEX
Dear R-users:
I can not reproduce figure 4 of *Statistical Tables and Plots using S and
LATEX* by Prof. Frank Harrell with the following code:
rm(list=ls())
library(Hmisc)
getHdata(pbc)
attach(pbc)
age.groups <- cut2(age, c(45,60))
g <- function(y) apply(y, 2, quantile, c(.25,.5,.75))
y <- with(pbc, cbind(Chol=chol,Bili=bili))
# You can give new column names that are not legal S names
2010 Sep 13
0
using survexp and ratetable with coxph object that includes a factor term
Hello,
I'm attempting to use the ratetable argument to
survexp in the survival package. I use
the example from the ?survexp help page below,
and then slightly modify it to produce an error.
library(survival)
data(pbc)
#fit a model without any factors
pfit1 <- coxph(Surv(time, status > 0) ~ trt + log(bili) +
log(protime) + age + platelet, data=pbc)
#this works as expected
2004 Apr 09
2
Regression models w/ splines
Hi - I am fitting various Cox PH models with spline predictors. After
fitting the model, I would like to use termplot() to examine the
functional form of the fitted model (e.g., to obtain a plot of the
relative risk (or log r.r.) versus the predictors).
When there is only 1 predictor in the model, termplot returns a "?".
In this case, I have not been able to figure out how to create
2024 Jun 15
1
Hard crash of lme4 in R-devel
I ran across this by accident when working up an example. It uses a data set from the survival package, but nothing else from there. Fails on the Intel machine shown below, and on a virtual linux instance on a newer Mac.
Terry
> library(survival)
> library(lme4)
Loading required package: Matrix
> sessionInfo()
R Under development (unstable) (2024-06-14 r86747)
Platform:
2011 Jul 08
4
Using t tests
Dear Sir,
I am doing some work on a population of patients. About half of them are
admitted into hospital with albumin levels less than 33. The other half have
albumin levels greater than 33, so I stratify them into 2 groups, x and y
respectively.
I suspect that the average length of stay in hospital for the group of
patients (x) with albumin levels less than 33 is greater than those
2006 Mar 26
1
Newbie clustering/classification question
My laboratory is measuring the abundance of various proteins in the
blood from either healthy individuals or from individuals with various
diseases. I would like to determine which proteins, if any, have
significantly different abundances between the healthy and diseased
individuals. Currently, one of my colleagues is performing an ANOVA on
each protein with MS Excel. I would like to analyze
2004 Oct 15
1
categorical varibles in coxph
Hello,
I wonder when I do coxph in R:
coxph( Surv(start, stop, event) ~ x, data=test)
If x is a categorical varible (1,2,3,4,5), should I creat four dummy
varibles for it? if yes, how can I get the overall p value on x other
than for each dummy variable?
Thanks
Lisa Wang
Princess Margaret Hospital
Phone 416 946 4501
2010 Oct 19
1
could not find function "hmatplot"
I need a picture like this:
http://rwiki.sciviews.org/doku.php?id=graph_gallery:graph38
http://rwiki.sciviews.org/doku.php?id=graph_gallery:graph38
but when I try compile it
require("hexbin")
data(NHANES)# pretty large data set!
good <- !(is.na(NHANES$Albumin) | is.na(NHANES$Transferin))
NH.vars <- NHANES[good,
2009 Sep 21
2
cox memory
Hi there,
I have a rather large data set and perform the following cox model:
test1 <- list(tstart,tstop,death1,chemo1,radio1,horm1)
out1<-coxph( Surv(tstart,tstop, death1) ~ chemo1+chemo1:log(tstop+1)+horm1+horm1:log(tstop+1)+age1+grade1+grade1:log(tstop+1)+positive1+positive1:log(tstop+1)+size1+size1:log(tstop+1), test1)
out1
Up to here everything works fine (with each covariate
2009 Feb 23
2
array manipulation simple questions
Hi there,
I am pretty new to R. Actually I started using it yesterday. I have two questions:
1. Suppose I have a<-c(1:10) (or a<-array(c(1:10),dim=c(1,10)))
and I want to end up with vector b=[0 0 0 0 0 1 1 1 1 1]. i.e. I want to substitute alla elements that are <5 with 0 and >5 with 1.
I did this by using a for loop. Is there another function to use so as to avoid the
2009 Mar 10
2
simple question beginner
Hi there,
I am beginner in R and I have some basic question. Suppose I run a common procedure such as a t test or cox model like below:
out<-coxph( Surv(tstart,tstop, death1) ~ x1+x1:log(tstop+1) , test1,method=c("breslow"))
Which yields the following result:
Call:
coxph(formula = Surv(tstart, tstop, death1) ~ x1 + x1:log(tstop +
1), data = test1, method =
2008 Oct 14
1
library MICE warning message
Hello.
I have run the command
imp<-mice(mydata, im=c("","pmm","logreg","logreg"),m=5)
for a variable with no missing data, a numeric one and two variables with binary data.
I got the following message:
There were 37 warnings (use warnings() to see them)
> warnings()
Warning messages:
1: In any(predictorMatrix[j, ]) ... : coercing argument of
2009 Oct 27
2
cox regression extract strata as numeric
Hi there,
I perform a stratified cox and then I need the strata as a numeric array "straft.ln"
ft.ln <- coxph(Surv(times,deaths)~ages+chemos+chemos:f1+chemos:f2+horms+horms:f1+horms:f2+grades+grades:f1+grades:f2+positives+positives:f1+positives:f2+sizes+sizes:f1+sizes:f2+strata(stra),data=ddd)
basehazzft.ln=basehaz(ft.ln,centered=FALSE)
H0ft.ln=c(basehazzft.ln[,1])
2008 Jan 29
2
Direct adjusted survival?
Hello,
I am trying to find an R function to compute 'direct adjusted survival'
with standard errors. A SAS-macro to do this is presented in Zhang X,
Loberiza FR, Klein JP, Zhang MJ. A SAS macro for estimation of direct
adjusted survival curves based on a stratified Cox regression model.
Comput Methods Programs Biomed 2007;88:95-101. It appears that this
method is not implemented in R.