search for: unstratified

Displaying 4 results from an estimated 4 matches for "unstratified".

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2005 Apr 29
0
problem with strata in boot
...having trouble running a stratified bootstrap. My data set consists of 38 study sites in which I recorded the number of bird pairs. Each site has been classified as burned or mowed and for each of these two strata I would like to determine the precision of an overall density estimate. I can run an unstratified bootstrap without problem, but when I specify the strata I get the same unstratified result. cswafun <- function(denboot, i) sum(cswa[i])/(sum(parea[i]) attach(denboot) cswa.boot <- boot(denboot, cswafun, R = 10000, strata = treat) ### cswa is a vector of integers representing the number o...
2007 May 17
1
Stratified Cox proportional Hazard Model
Hello everyone, I am a new user of R. Does anybody know how hazard ratios are extracted for each factor level in a stratified Cox proportional hazard regression model? I have a cancer data set where the variable ?differentiation? is a factor with three levels: poor, intermediate and good. I would like to extract the hazard ratio for each grade level and relate it to another prognostic factor.
2006 Jun 18
1
Post Stratification
Dear WizaRds, having met some of you in person in Vienna, I think even more fondly of this community and hope to continue on this route. It was great talking with you and learning from you. Thank you. I am trying to work through an artificial example in post stratification. This is my dataset: library(survey) age <- data.frame(id=1:8, stratum=rep(
2009 Apr 25
3
Nomogram with stratified cph in Design package
Hello, I am using Dr. Harrell's design package to make a nomogram. I was able to make a beautiful one without stratifying, however, I will need to stratify to meet PH assumptions. This is where I go wrong, but I'm not sure where. Non-Stratified Nomogram: