Hi all, I would like to run a paired t-test with censored data using the NADA package. Here is an example data set: data <- data.frame(group=rep(c('a','b'), each=6), obs=c(2,2,5,7,10,10,5,5,6,8,5,9), cen=c(T,T,F,F,F,F,F,F,F,F,F,F)) #A two sample t-test can be executed as follows: library(NADA) cendiff(data$obs, data$cen, data$group) Does anybody know how to extend this to conduct a paired t-test based on the difference between paired observations of groups A and B? Many thanks, Jake =================================Jake J. Beaulieu, PhD US Environmental Protection Agency National Risk Management Research Lab 26 W. Martin Luther King Drive Cincinnati, OH 45268 USA 513-569-7842 (desk) 513-487-2511 (fax) beaulieu.jake@epa.gov [[alternative HTML version deleted]]