rats {survival}R Documentation

Rat treatment data from Mantel et al


Rat treatment data from Mantel et al. Three rats were chosen from each of 100 litters, one of which was treated with a drug, and then all followed for tumor incidence.


data(cancer, package="survival")


litter: litter number from 1 to 100
rx: treatment,(1=drug, 0=control)
time: time to tumor or last follow-up
status: event status, 1=tumor and 0=censored
sex: male or female


Since only 2/150 of the male rats have a tumor, most analyses use only females (odd numbered litters), e.g. Lee et al.


N. Mantel, N. R. Bohidar and J. L. Ciminera. Mantel-Haenszel analyses of litter-matched time to response data, with modifications for recovery of interlitter information. Cancer Research, 37:3863-3868, 1977.


E. W. Lee, L. J. Wei, and D. Amato, Cox-type regression analysis for large number of small groups of correlated failure time observations, in "Survival Analysis, State of the Art", Kluwer, 1992.

[Package survival version 3.6-4 Index]