Displaying 4 results from an estimated 4 matches for "strgender".
2008 Dec 28
1
cox regression warning/error messages
...at plots should be run for each dummy variable, or is it
correct simply to run the analysis on the original variable?
The code employed to generate the analysis follows:
Any assistance is appreciated,
Bob
cox.NV <- coxph(Surv(recidivism$intDaysUntilFNVPO,
recidivism$Event_nv) ~ recidivism$strGender +
recidivism$intAgeAtMHCIndex + recidivism$PRE.nv + group +
recidivism$MHC.nv + recidivism$SNFP , data = recidivism)
> summary(cox.NV)
Call:
coxph(formula = Surv(recidivism$intDaysUntilFNVPO, recidivism$Event_nv) ~
recidivism$strGender + recidivism$intAgeAtMHCIndex + recidivism$PRE.nv +...
2009 Mar 14
1
obtaining the values for the hazard function in a cox regression
...s occurring in the log plots.
Below is the code that I have been using. Any assistance is appreciated,
regards
Bob
library(survival)
recidivismv <- read.csv("g://Chapsurv_v.csv",header=T)
cox.V <- coxph(Surv(intDaysUntilFVPO, Event_v) ~ intAgeAtMHCIndex +
PRE + group + MHC + strGender, data = recidivismv)
summary (cox.V)
# produces a log-log plot
mvfit <- survfit (Surv(recidivismv$intDaysUntilFVPO,
recidivismv$Event_v) ~ MHC, data = recidivismv)
neg.ll <- function(mvfit) -log(-log(mvfit))
library (Design)
survplot(mvfit, fun = neg.ll, conf = "none", logt=TRUE...
2009 Mar 16
0
hazard function in a Cox model
...rrect command to obtain such values, to
better understand what is occurring in the log plots.
--- end inclusion ----
The best tool for understanding what is happening is cox.zph.
cox.V <- coxph(Surv(intDaysUntilFVPO, Event_v) ~ intAgeAtMHCIndex +
PRE + group + MHC + strGender, data = recidivismv)
zpfit <- cox.zph(cox.V, transform='identity')
plot( zpfitp[1]) #plot for the first variable
plot( zpfitp[2]) #plot for the second
You will get a plot of beta(t) versus time, a horizontal line corresponds to a
constant hazard ratio. The Cox model coeffi...
2009 Mar 28
1
stratified variables in a cox regression
...ode - is there a method to test whether the
stratified variables should be included in the final model at all?
library(survival)
recidivismv <- read.csv("g://Chapsurv_v.csv",header=T)
cox.V2 <- coxph(Surv(intDaysUntilFVPO, Event_v) ~ intAgeAtMHCIndex +
PRE + group + strata (MHC, strGender), data = recidivismv)
regards
Bob