In: Statistics and Probability
The probability of getting a false-positive result for a single person, was 0.3%.
What would be the new approximate percentage probability of getting at least one false-positive result, if 650 people had been tested, instead of 550?
What would be the new approximate percentage probability of getting at least one false-positive result, if 550 people are still tested, but the probability of getting a false-positive result for a single person was 0.4% instead of 0.3% ?
The probability of getting a false positive result for a single person is 0.3%.
So, the chance of not being a false positive case is
Now, 650 people are tested. We have to find the chance that at least one result was false positive.
This is complementary to the event that none was false positive.
So, the required probability is
So, the answer is 0.8581.
Now, the probability of false positive is 0.4%.
So, the probability of not being false positive is
Now, 550 people are tested. We have to find the chance that at least one case is false positive.
This is complementary to the event that none is false positive.
So, the required probability is
So, the answer is aproximately 0.99.