SOLUTION: ARE MY ANSWER CORRECT? A certain virus infects one in every 600 people. A test used to detect the virus in a person is positive 90% of the time if the person has the virus and

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Question 1061642: ARE MY ANSWER CORRECT?

A certain virus infects one in every 600 people. A test used to detect the virus in a person is positive 90% of the time if the person has the virus and 10% of the time if the person does not have the virus. Let A be the event "the person is infected" and B be the event "the person tests positive."
(a) Find the probability that a person has the virus given that they have tested positive.

0.1013

(b) Find the probability that a person does not have the virus given that they have tested negative.
-53.82
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
Use a large number, like 60000
====D+=====D-======
T+===90====5990=======6080
T-===10=====53910=====53920
Total=100=====59900=====60000
This has 90/100 or 90% of people who have the virus and 10% of them who don't have it.
Given they test positive (6080), 90 have the virus (0.0148).
Given that they test negative (53920), 53910 do not have it (99.98%).