.
One individual is randomly selected from 500:
Wrinkles Wrinkles
Prominent Not Prominent
Heavy Smoker 120 60
Light Smoker 75 245
(a) Given that the individual is a heavy smoker, what is the
probability that he/she does not have prominent wrinkles?
(b) What is the probability that the selected individual is a
heavy smoker or has prominent wrinkles?
~~~~~~~~~~~~~~~~~~~~~~~
Solution
(a) Given that the individual is a heavy smoker, we look into the first line
in the table, only, and take the values from there.
Doing this way, for the probability under the question, we get
P =
=
=
. ANSWER
(b) In (b), the individual is randomly selected from the total of 500.
Therefore, P =
=
= 0.51. ANSWER
Solved.