survey (version 3.12)

svykm: Estimate survival function.

Description

Estimates the survival function using a weighted Kaplan-Meier estimator. Standard errors are not currently available.

Usage

svykm(formula, design, ...)
## S3 method for class 'svykm':
plot(x,xlab="time",ylab="Proportion surviving",
  ylim=c(0,1),...)
## S3 method for class 'svykm':
lines(x,xlab="time",type="s",...)
## S3 method for class 'svykmlist':
plot(x, pars=NULL, ...)
## S3 method for class 'svykm':
quantile(x, probs=c(0.75,0.5,0.25),...)

Arguments

formula

Two-sided formula. The response variable should be a right-censored Surv object

design

survey design object

...

in plot and lines methods, graphical parameters

x

a svykm or svykmlist object

xlab,ylab,ylim,type

as for plot

pars

A list of vectors of graphical parameters for the separate curves in a svykmlist object

probs

survival probabilities for computing survival quantiles (note that these are the complement of the usual quantile input

Value

• For svykm, an object of class svykm for a single curve or svykmlist for multiple curves.

See Also

svycoxph

Examples

data(pbc, package="survival")
pbc$randomized <- with(pbc, !is.na(trt) & trt>0)
biasmodel<-glm(randomized~age*edema,data=pbc)
pbc$randprob<-fitted(biasmodel)

dpbc<-svydesign(id=~1, prob=~randprob, strata=~edema, data=subset(pbc,randomized))

s1<-svykm(Surv(time,status>0)~1, design=dpbc)
s2<-svykm(Surv(time,status>0)~I(bili>6), design=dpbc)

plot(s1)
plot(s2)
plot(s2, lwd=2, pars=list(lty=c(1,2),col=c("purple","forestgreen")))

quantile(s1, probs=c(0.9,0.75,0.5,0.25,0.1))