set.seed(123)

t0 <- data.frame(id=seq(1, 100, length.out=100), t0=sample(c(0,1),100, replace=TRUE, prob=c(0.9, 0.1)))
t1 <- data.frame(t1=sample(c(0,1),100, replace=TRUE, prob=c(0.9, 0.1)))
t2 <- data.frame(t2=sample(c(0,1),100, replace=TRUE, prob=c(0.9, 0.1)))
t3 <- data.frame(t3=sample(c(0,1),100, replace=TRUE, prob=c(0.9, 0.1)))
t4 <- data.frame(t4=sample(c(0,1),100, replace=TRUE, prob=c(0.1, 0.9)))
t5 <- data.frame(t5=sample(c(0,1),100, replace=TRUE, prob=c(0.9, 0.1)))
t6 <- data.frame(t6=sample(c(0,1),100, replace=TRUE, prob=c(0.9, 0.1)))

dat <- data.frame(t0,t1,t2,t3,t4,t5,t6)


m <- as.matrix(dat)
nr <- as.vector(0)

for(i in 1:4){
  ids <- m[which(m[ ,(2+(i-1))] %in% 0), 1];
   b <- m[ids, (3+(i-1)):(5+(i-1))]
  c <- apply(b, 1, function(x) any(x %in% 1))
 nr[i] <- nrow(b[c, ])/length(ids)
}