intcox.example {intcox} | R Documentation |
Weibull distributed survival times with four covariates interval censored by a fixed grid
data(intcox.example)
A data frame with 200 observations on the following 6 variables.
[-1,1]
distributed covariate
The example dataset consists of 200 Weibull distributed random variables with shape=0.75
,
while scale
is derived from (1/λ)^(1/shape) with λ = exp{β_0+β'X}
where β = {0.5,-0.5,0.5,0.5}' and design matrix X
which is formed by the four covariates.
Furthermore, an interval was generated where the left interval end is zero
and the right interval end is defined by maximum value (T.max
) of the which is got by
the 0.9-quantile of a Weibull r.v. with shape=0.75
and scale=median(scale)
.
If the value of event time >=T.max
then the event time is right censored (left=T.max
and right=NA
).
Otherwise the interval [0,T.max]
was randomly divided into subintervals (grid=10
) in order to determine
the corresponding interval ends for each event time which is not right censored.
The generating code is given below.
## Not run: sim.weibull.intcox.rfc <-function (N=200,beta.0=0.1,beta.cov=c(0.5,-0.5,0.5,0.5),alpha=0.75,p.cov=c(0.5,0.75),grid=10) { x.design<-cbind(rbinom(N,1,p.cov[1]),rbinom(N,1,p.cov[2]),runif(N,-1,1),rnorm(N,0,1)) colnames(x.design)<-paste("x.",1:4,sep="") lambda<-exp(beta.0+x.design%*%matrix(beta.cov,ncol=1)) scale<-(1/lambda)^(1/alpha) t.true<-rweibull(N,alpha,scale) T.max<-max(qweibull(0.9,alpha,median(scale))) t.left<-NULL t.right<-NULL for (i in 1:N) { tt<-unique(c(0,sort(runif(grid,0,T.max)),T.max)) if (t.true[i]>=T.max) { x.left<-T.max x.right<-NA } else { x.left<-max(tt[t.true[i]>tt]) x.right<-min(tt[t.true[i]<tt]) } t.left<-c(t.left,x.left) t.right<-c(t.right,x.right) } return(data.frame(ID=1:N,left=t.left,right=t.right,x.design)) } ## End(Not run) data(intcox.example)