Question

Glen is being tested for a contagious disease. The test is 99% accurate and in actuality 0.1% of the population has the disease. Should Glen demand to be retested or start treatment right away? Explain.

Answer 1

The answer is B. Glen should demand to be retested as the probability that he has the disease given he test positive is only 0.08

Explanation:

You are looking for a conditional probability. P(has disease given he tested positive).

This probability is 9 /109 = 0.082. Which means that there is only an 8% chance that he actually has the disease for a test that is 99% accurate.

Therefore, Glen should demand to be retested as the probability that he has the disease given he tested positive is only 0.08

Answer 2

I think Glen should demand to be rested than start treatment right away. Although the test is 99% accurate and only .1% of the population has the disease, there is no assurance that he will not get included in the .1% of the population. Also, he should be retested for the sake of reliability.