Question

On discovering that her family had a 70% risk of heart attack, Erin took a treadmill test to check her own potential of having a heart attack. The doctors told her that the reliability of the stress test is 67%. What is the probability that Erin will have a heart attack and the test predicts it?

A. 0.099

B. 0.201

C. 0.231

D. 0.469

Answer 1

I'm not 100% sure, but say
\(H\) = potential for heart attack
\(T\) = test predicts it

Then you are given
\( P(H)=0.7\)
\(P(T|H) = 0.67\), I believe that reliability is saying what the probability of test predicting it given that you have a potential for heart attack

So then you are asked to find \(P(T \cap H)\).

\[P(T|H)=\frac{P(T \cap H)}{P(H)} \implies P(T \cap H)=P(T|H)P(H)=0.67*0.7\]