After your yearly checkup, the doctor has bad news and good news. The
bad news is that you tested positive for a serious disease and that the test is 99% accurate (i.e., the
probability of testing positive when you do have the disease is 0.99, as is the probability of testing
negative when you don’t have the disease). The good news is that this is a rare disease, striking
only 1 in 10,000 people of your age.