A medical test is available to determine whether a patient has a certain disease. To determine the accuracy of the test, a total of 10,100 people are tested. Only 100 of these people have the disease, while the other 10,000 are disease free. Of the disease-free people, 9800 get a negative result, and 200 get a positive result. The 100 people with the disease all get positive results. Use this information as you answer the questions below.

1) Find the probability that the test gives the correct result for a person who does not have the disease.

2) Find the probability that the test gives the correct result for a person who has the disease.

3) Given that a person gets a positive result, what is the probability that the person actually has the disease?

Why are medical tests repeated? For many medical tests, if the result comes back positive, the test is repeated. Why do you think this is done?