Dear R-listers,
Does anybody know what is the correct source of "rats" dataset in survival
package?
The help gives the following information:
Rat data from survival5
Description:
48 rats were injected with a carcinogen, and then randomized to
either drug or placebo. The number of tumors ranges from 0 to 13;
all rats were censored at 6 months after randomization.
Usage:
data(rats)
Format:
rat: id
rx: treatment,(1=drug, 0=control)
observation: within rat
start: entry time
stop: exit time
status: event status
Source:
Gail, Sautner and Brown, Biometrics 36, 255-66, 1980
but "rats" data.frame contains the variables:
names(rats)
[1] "litter" "rx" "time" "status"
It seems to be 150 rats grouped in 50 litters, and 1 mouse is treated at each
one. So this dataset does not agree with the description above mentioned.
I am very interesting in knowing the reference of this data.
PS/ BTW, the correct source of rats injected with a carcinogen is Gail,
Santner and Brown,...
Thanks you very much in advance,
Juan
[[alternative HTML version deleted]]
______________________________________________
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
