Question

Imagine that zika virus has a 1% incidence in the population. A test for the virus has a 3% false positive rate and no false negative rate. If someone takes the test and gets a positive result, what is the chance that they are infected?

Answer 1

Answer:

There is 97% Chance that the person is infected.

Explanation:

According to the question, the test for the virus has 3% false positive and there is no false negative rate.

Therefore if someone takes the test and gets a positive result, the chances of the person to be infected ( True positive ) is

100 - 3 = 97%

Note: False positive result is a result that indicates that a given condition is present when it is not actually present.

Answer 2

Answer:

The answer is 97%.

Explanation:

The zika virus' 1% incidence rate in the population has no effect over the probability of the patient being infected or not. If the test has a 3% false positive rate that means that if it is positive, the results have a 97% chance of being true. Therefore the chance that the person who took the test and had a positive result being actually infected is 97%.

I hope this answer helps.