Question

Two conditions that often occur together in an older population are high blood pressure (B) and diabetes (D), with at least one condition occurring 50% of the time. Suppose the P(B|D) = 0.7 and the P(D)=0.3. What is the probability that a randomly chosen individual has high blood pressure? Answer to two decimal places.

Answer 1

Solution:

Given ,

P(B D) = 50% = 0.5

P(B | D) = 0.7

P(D) = 0.3

We know that ,

P(B | D) = P(B D) / P(D)

0.7 =   P(B D) / 0.3

   P(B D) = 0.21

Now ,

P(B D) = P(B) + P(D) -  P(B D)

0.5 = P(B) + 0.3 - 0.21

P(B) = 0.41

Answer : 0.41