[R] survfit plot question

[Andrews, Chris]

1. A censored observation
2. It does not relate to either
3. See ?print.survfit  .  Recall also that the mean of a positive random variable is the integral from 0 to infinity of the survival function.  The truncated mean is the integral from 0 to tau (819 in your case) of the survival function.

Chris


-----Original Message-----
From: Steve Einbender [mailto:steve.einbender at gmail.com] 
Sent: Monday, March 04, 2013 7:44 AM
To: r-help
Subject: [R] survfit plot question

Hello,
I create a plot from a coxph object called fit.ads4:
plot(survfit(fit.ads4))

plot is located at:
https://www.dropbox.com/s/9jswrzid7mp1u62/survfit%20plot.png

I also create the following survfit statistics:

> print(survfit(fit.ads4),print.rmean=T)
Call: survfit(formula = fit.ads4)

   records      n.max    n.start     events     *rmean *se(rmean)
median    0.95LCL    0.95UCL
     203.0      100.0      100.0      103.0      486.7       24.4
 387.0      340.0      467.0
    * restricted mean with upper limit =  819


Questions:
1.  What is the cross mark in the plot ?
2.  How does the cross mark in the plot relate to either the "rmean" or the "median" from survfit ?
3.  What is the meaning of the "restricted mean" ?  The "upper limit" noted in the output is the "end of the observation period" (i.e., it is always the Stop value in the Censored observation)

Thanks for taking the time to review

Steve

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