# numerical rules
age >= 0
height > 0
age <= 150
age > yearsmarried

# categorical rules
status %in% c("married", "single", "widowed")
agegroup %in% c("child", "adult", "elderly")
if ( status == "married" )  agegroup %in% c("adult","elderly")

# mixed rules
if ( status %in% c("married","widowed"))  age - yearsmarried >= 17
if ( age < 18 )              agegroup == "child"
if ( age >= 18 && age <65 )  agegroup == "adult"
if ( age >= 65 )             agegroup == "elderly"