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...nt error distributions 2. Have the error term be dependent on the covariates But I'm not sure how to specify either conditions. I am using the Design package to perform the survival analysis using the survreg, bj, coxph functions. Any help is greatly appreciated. This is what I have so far: survtime <- 10*rexp(500) #distribution of survival time cens <- ifelse(survtime > 10, 0, 1) #indicator for censored/observed survtime <- pmin(survtime, 10) #new survival time values with censored info age <- rnorm(200, 40, 10) #age variable race <- factor(sample(c('a','b...

i would like to add a variable to an existing matrix by manipulating 2 previous variables eg for the data m treat strata censti survTime [1,] 1 2 284.684074 690.4961005 [2,] 1 1 172.764515 32.3990335 [3,] 1 1 2393.195400 24.6145279 [4,] 2 1 30.364771 8.0272267 [5,] 1 1 523.182282 554.7659501 l would want to add a new column censoring by comparing (...

hie l would like to create a 6th column "actual surv time" from the following data the condition being if censoringTime>survivaltime then actual survtime =survival time else actual survtime =censoring time the code l used to create the data is s=2 while(s!=0){ n=20 m<-matrix(nrow=n,ncol=4) colnames(m)=c("treatmentgrp","strata","censoringTime","survivalTime")...

Dear useRs, I am trying to fit a Cox PH model on survival data from a lung cancer dataset. I would like to include the patient staging (I-IV) as a covariate. For this I use the following function: coxph(Surv(time,status) ~ stage) The staging information is a categorical variable, and it is important to take the ordering into account (I<II<III<IV). Does the coxph function handle

Hello, Can anyone suggest a simple way to generate a Kaplan-Meier plot with 2 survfit objects, just like this one:? https://drive.google.com/file/d/1fEcpdIdE2xYtA6LBQN9ck3JkL6-goabX/view?usp=sharing Suppose I have 2 survfit objects: fit1 is for the curve on the left (survtime has been truncated to the cutoff line: year 5), fit2 is for the curve on the right (minimum survival time is at the cutoff line: year 5), but if I do the following: plot(fit1, col=1:2) lines(fit2,col=1:2) Then I will have an horizontal line on the top that connect from 0 to 4 years, which I do n...

Hi all, Is there an equivalent to predict(...,type="linear") of a Proportional hazard model for a Cox model instead? For example, the Figure 13.12 in MASS (p384) is produced by: (aids.ps <- survreg(Surv(survtime + 0.9, status) ~ state + T.categ + pspline(age, df=6), data = Aidsp)) zz <- predict(aids.ps, data.frame(state = factor(rep("NSW", 83), levels = levels(Aidsp$state)), T.categ = factor(rep("hs", 83), levels = levels(Aidsp$T.categ)), age = 0:82), se = T, type = "li...

I'm trying to convert a dataset from the time-independent analysis form > head(addicts) id clinic status survtime prison meth clinic01 1 1 1 1 428 0 50 1 2 2 1 1 275 1 55 1 3 3 1 1 262 0 55 1 into the "counting data format" necessary to perform extended Cox regression. I got survSplit() to work, but it appear...

...) ind<-which(R==j) dati[i,]<-c(obsTime[j],status[j],x[j]) filtro<-R!=j R<-R[filtro] Pok<-Pok[,filtro] } dati[nrow(dati),]<-c(obsTime[nrow(dati)],status[nrow(dati)],x[nrow(dati)]) dati<-data.frame(dati) names(dati)<-c("SurvTime","cens","x") library(survival) coxph(Surv(SurvTime,cens)~x,dati)

...ovariates and FAILCENS = 2 indicates observed times. So, when I tried to use, igg2.long<-unfold(igg.2[3,],time="FAILTIME",event="FAILCENS",cov=9:13,cov.na mes="iggtitre"), I obtained the following output: start stop FAILCENS.time CASE TRT FAILTIME FAILCENS SURVTIME SURVCENS SEX 3.1 0 1 0 26003 A 11.2033 1 17.5441 1 1 3.2 1 2 0 26003 A 11.2033 1 17.5441 1 1 3.3 2 3 0 26003 A 11.2033 1 17.5441 1 1 3.4 3 4 0 26003 A 11.2033...

Hello all- I am doing a survival analysis for two species of invasive plants I outplanted to edges and interiors of island and mainland sites in a local reservoir. I am using the KM estimate and had no problem doing survdiff for my data using the following code: S4<-Surv(outplant$SurvTime, outplant$StatusD6) diff4=survdiff(S4 ~ outplant$Species+outplant$SiteType+outplant$EdgInt) diff4 Species = ALBIJU or LONIJA SiteType = Island or Mainland EdgInt = Edge or Interior The overall test for difference among the 8 curves is highly significant (p<0.001), but what I would like to kno...

...ate a Kaplan-Meier plot with 2 survfit objects, just like this one: > > > > > > > > https://drive.google.com/file/d/1fEcpdIdE2xYtA6LBQN9ck3JkL6-goabX/view?usp=sharing > > > > > > > > Suppose I have 2 survfit objects: fit1 is for the curve on the left (survtime has been truncated to the cutoff line: year 5), fit2 is for the curve on the right (minimum survival time is at the cutoff line: year 5), but if I do the following: > > > > > > > > plot(fit1, col=1:2) > > > > lines(fit2,col=1:2) > > > > > > &gt...

Hi, How can I specify a Cox proportional hazards model with a covariate which i believe its strength on survival changes/diminishes with time? The value of the covariate was only recorded once at the beginning of the study for each individual (e.g. at the diagnosis of the disease), so I do not have the time course data of the covariate for any given individual. For example, I want to state at the