A certain virus infects one in every 400 people. A test used to detect the virus in a person is positive 90% of the time if the person has the virus and 8% of the time if the person does not have the virus. (This 8% result is called a false positive.) 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, i.e. find P(A|B). Round your answer to the nearest tenth of a percent and do not include a percent sign. P(A|B)- b) Find the probability that a person does not have the virus given that they test negative, i.e. find P(A'|B'). Round your answer to the nearest tenth of a percent and do not include a percent sign. P(A'|B') =
A certain virus infects one in every 400 people. A test used to detect the virus in a person is positive 90% of the time if the person has the virus and 8% of the time if the person does not have the virus. (This 8% result is called a false positive.) 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, i.e. find P(A|B). Round your answer to the nearest tenth of a percent and do not include a percent sign. P(A|B)- b) Find the probability that a person does not have the virus given that they test negative, i.e. find P(A'|B'). Round your answer to the nearest tenth of a percent and do not include a percent sign. P(A'|B') =
A First Course in Probability (10th Edition)
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A certain virus infects one in every 400 people. A test used to detect the virus in a person is positive 90% of
the time if the person has the virus and 8% of the time if the person does not have the virus. (This 8% result
is called a false positive.) 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, i.e. find P(A|B).
Round your answer to the nearest tenth of a percent and do not include a percent sign.
P(A|B)=
b) Find the probability that a person does not have the virus given that they test negative, i.e. find
P(A'|B'). Round your answer to the nearest tenth of a percent and do not include a percent sign.
P(A'|B') =
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Transcribed Image Text:M0/1
A certain virus infects one in every 400 people. A test used to detect the virus in a person is positive 90% of
the time if the person has the virus and 8% of the time if the person does not have the virus. (This 8% result
is called a false positive.) 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, i.e. find P(A|B).
Round your answer to the nearest tenth of a percent and do not include a percent sign.
P(A|B)=
b) Find the probability that a person does not have the virus given that they test negative, i.e. find
P(A'|B'). Round your answer to the nearest tenth of a percent and do not include a percent sign.
P(A'|B') =
Question Help: D Video
Submit Question
9%
e here to search
***
F12
Prisc
** FIL
F10
F9
F7
&
%23
6
7
3
4.
Y
U
IT
E
11
J
G
S
C
Ctri
Alt
Alt
Expert Solution
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Step 1
Let's draw tree diagram from given information ,
A : Event that the person is infected
P( A ) = 1/400 = 0.0025
B : Event that the person tests is positive.
we have ,
P( A ) = 0.0025 , P( A') = 0.9975
P( B | A ) = 0.9 , P( B' | A ) = 0.1
P( B | A' ) = 0.08 , P( B' | A' ) = 0.92
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