In: Statistics and Probability
Suppose that 5 percent of the population of a certain town contracted the COVID19 virus. There is a medical diagnostic test for detecting the disease. But the test is not very accurate. Historical evidence shows that if a person has the virus, the probability that her/his test result will be positive is 0.9. However, the probability is 0.15 that the test result will be positive for a person who does not have the virus.
1. Define clearly the events before you answer the following questions.
2. For a person selected randomly from the town, the test result was positive. What is the probability that the person has the Corona virus?
3. What is the difference between the probability found in the previous question and the 5%? How do we call the two probabilities?
4. For a person selected randomly from the town, the test result was negative. What is the probability that the person has the Corona virus?
5. For a person selected randomly from the town, the test result was positive. What is the probability that the person does not have the Corona virus?