
Explanation:
Let's go step by step.
Step 1: Define events
Let:
Given:
Correct positive diagnosis means test is positive given the person has the disease. So:
Correct negative diagnosis means test is negative given the person does not have the disease. So:
That means:
Step 2: Apply Bayes’ theorem
We want :
Substitute:
Step 3: Interpret result
The probability that a person has the disease given a positive test is about 96.94%.
Ultimate access to all questions.
A test for heart disease results in a correct positive diagnosis 95% of the time and a correct negative diagnosis 99% of the time. 25% of the population has heart disease. What is the probability that a person has the disease given that the test is positive?
A
0.275
B
0.15
C
0.245
D
0.97