Who survived?

extensional passenger(id: integer, survived: integer, class: integer, sex: string, fare: float).

Since survived is 0 or 1, its average is the survival rate:

survival_by_sex(Sex, avg(Survived), count(_)) :-
    passenger(_, Survived, _, Sex, _).

Sex	rate	N
female	0.74	314
male	0.19	577

survival_by_class(Class, avg(Survived), count(_)) :-
    passenger(_, Survived, Class, _, _).