Answer Using R

Let sex = c(1,1,1,1,1,2,2,2,2,2); smoking = c(1,0,1,0,1,0,0,0,1,1); age=c(21:30) in R. A data frame is constructed as zz = data.frame(sex, smoking, age). Give the results of following R commands:

1. apply(zz[-1,], 2, min)
2. zz[zz[,3]>24,]
3. zz[order(zz["smoking"], zz["age"]), ]
4. subset(zz, zz["sex"]==2)
5. tapply(zz$age, zz$smoking, max)
6. apply(zz[,-3], 1, function(x){ sum(x) })