Question

In an experiment to study the relationship of hypertension
and smoking habits, the following data are
collected for 180 individuals:
Moderate Heavy
Nonsmokers Smokers Smokers
H 21 36 30
NH 48 26 19
where H and NH in the table stand for Hypertension
and Nonhypertension, respectively. If one of these individuals
is selected at random, find the probability that
the person is
(a) experiencing hypertension, given that the person is
a heavy smoker;
(b) a nonsmoker, given that the person is experiencing
no hypertension.