# New strain of flu

## Question

You go to see the doctor about a cough you've had for a while. The doctor selects you at random to have a blood test for a new strain of flu, which for the purposes of this exercise we will say is currently suspected to affect 1 in 10,000 people in the US. The test is 99% accurate, in the sense that the probability of a false positive is 1%. The probability of a false negative is zero. You test positive. What is the new probability that you have this strain of flu?