Graphical test of proportional hazards
Usage
plot.cox.zph(x, resid=T, se=T, df=4, nsmo=40, var)
Arguments
x
|
result of the cox.zph function.
|
resid
|
include the residuals on the plot, as well as the smooth fit.
|
se
|
if true, confidence bands at 2 standard errors will be added.
|
df
|
the degrees of freedom for the fitted natural spline. A df value of
2 leads to a linear fit.
|
nsmo
|
number of points used to plot the fitted spline.
|
var
|
the set of variables for which plots are desired. By default, plots are
produced in turn for each variable of a model. Selection of a single variable
allows other features to be added to the plot, e.g., a horizontal line at
zero or a main title.
|
Side Effects
a plot is produced on the current graphics device.See Also
cox.zph
, coxph
Examples
data(veteran)
vfit <- coxph(Surv(time,status) ~ trt + factor(celltype) + karno +age,
data=veteran, x=T)
temp <- cox.zph(vfit)
plot(temp, var=5) #Look at Karnofsy score
abline(0,0, lty=3)
abline( lm( temp$y[,5] ~ temp$x), lty=4) #Add the linear fit as well
title(main="VA Lung Study")