* commands for Problems 13.9-10 of VER (following the solution)

use "H:\VHM\VHM811\henriks\calf.dta", clear
keep sepsis age attd umb
egen age_c2=cut(age), at(0,7,99)
egen attd_c2=cut(attd), at(0,2,99)

* Problem 13.9
cs sepsis attd_c2, by(age_c2)
cs sepsis umb, by(age_c2)
cs sepsis age_c2 if attd_c2==0
cs attd_c2 age_c2
cs umb age_c2
cs umb attd_c2, by(age_c2)

* Problem 13.10
cs sepsis umb if age_c2==7
cs sepsis umb if age_c2==0