Do I have the disease?

Let’s say there is a disease that affects, on average, 2% of people. There is a test for this disease.

• If someone who has the disease takes the test, the test will be positive 95% of the time.
• If someone who does not have the disease takes the test, the test will be positive 10% of the time.

You just took the test and it was positive. What’s the chance you have the disease?

Solution