Question

There are an equal number of males and females in your community. At any one time, 45% of the males have high blood pressure. At any one time, 4% of the women are pregnant.

What is the probability that the next person who comes into your emergency room will be either a hypertensive man or a pregnant woman? Show all work

Answer 1

Here, we are given that
P( high BP | males ) = 0.45
P( pregnant | females ) = 0.04

Also as there are equal number of males and females, we have here:
P( males ) = P( females ) = 0.5

Therefore the required probability that  the next person who comes into your emergency room will be either a hypertensive man or a pregnant woman is computed using the law of total addition of probability as:

= P( high BP | males )P( males ) + P( pregnant | females )P( females )
= 0.45*0.5 + 0.04*0.5
= 0.225+ 0.02
= 0.245

Therefore 0.245 is the required probability here.