1. The diagnostic test for COVID-19 virus has false positive rate 5% and false negative rate 20%. By last estimation, the COVID-19 infection rate is about 12%.

1(a). Determine the proportion of those testing positive that actually have the virus.

Enter the proportion in percent form. Round your percentage to 1 decimal place.

%

2. Blood donors are usually screened for HIV, both for the safety of the blood supply and for the benefit of the donor. The test, called an ELISA, tests positive 97.5% of the time if the donor actually has HIV. If the donor does not have HIV, the ELISA test correctly indicates that the person does not have the disease 92.6% of the time. About 0.2% of college students have HIV. After a blood drive at a college, the lab calls and tells a student that the test has indicated he has HIV.

2(a). Determine the probability that the student actually has HIV. (For the table approach it may be better to use 1,000,000 as your total population).

Enter your answer in percent form. Round the percentage to 1 decimal place.

%