Lupus is a medical phenomenon where antibodies that are supposed to attack foreign cells to prevent infections instead see plasma proteins as foreign bodies, leading to a high risk of blood clotting. It is believed that 2% of the population suffer from this disease. The test is 98% accurate if a person actually has the disease. The test is 74% accurate if a person does not have the disease.

Flag question: Question 6

What is the probability that a randomly selected person tests positive for the disease?

Flag question: Question 7

There is a line from the Fox television show that is often used after a patient tests positive for lupus: "It's never lupus." Suppose a randomly selected person tests positive for lupus. What is the probability the person actually has the disease?