Question 74534: use this data.
subject actually told the truth and polygraph indicated truth 65
subject actually told the truth and polygraph indicated lie 15
subject actually told a lie and polygraph indicated truth 3
subject actually told a lie and polygraph indicated lie 17
Q1. If 1 of the 100 subjects is randomly selected, find the probability of getting someone who told a lie.
Q2.If 1 of the 100 subjects is randomly selected, find the probability of getting someone for whom the polygraph test indicted that a lie was being told.
Q3.If 1 of the 100 subjects is randomly selected, find the probability of getting someone who told a lie or had the polygraph test indicated that a lie was being told.
Q4.If 1 of the 100 subjects is randomly selected, find the probability of getting someone who told the truth or had the polygraph test indicate that the truth was being told.
Q5. If 2 diffrent subjects are randomly selected, find the probability that they both told the truth.
Q6.If 2 different subjects are randomly selected, find the probability that they both had the polygraph test indicate that a lie was being told.
Q7.If 1 subject is randomly selected, find the probability that he or she told the truth, given that the polygraph test indicated that a lie was being told.
Q8. If 1 subject is randomly selected, find the probability that he or she has a polygraph test indication that a lie was being told, given that the subject actually told the truth.
Thank you i look forward to your answers.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! subject actually told the truth and polygraph indicated truth 65
subject actually told the truth and polygraph indicated lie 15
subject actually told a lie and polygraph indicated truth 3
subject actually told a lie and polygraph indicated lie 17
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Draw a "Contingency Table" with
two rows: Poly said true;and Poly said lied
two columns: Acutually told truth; Actually Lied
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Q1. If 1 of the 100 subjects is randomly selected, find the probability of getting someone who told a lie.
(3+17)/100 = 1/5
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Q2.If 1 of the 100 subjects is randomly selected, find the probability of getting someone for whom the polygraph test indicted that a lie was being told.
(15+17)/100 = 32/100
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Q3.If 1 of the 100 subjects is randomly selected, find the probability of getting someone who told a lie or had the polygraph test indicated that a lie was being told.
(20+3-17)/100 = 35/100
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Q4.If 1 of the 100 subjects is randomly selected, find the probability of getting someone who told the truth or had the polygraph test indicate that the truth was being told.
(80+68-65)/100 = 83/100
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Q5. If 2 different subjects are randomly selected, find the probability that they both told the truth.
80C2/100C2 = 0.638...
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Q6.If 2 different subjects are randomly selected, find the probability that they both had the polygraph test indicate that a lie was being told.
32C2/100C2 = 0.100...
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Q7.If 1 subject is randomly selected, find the probability that he or she told the truth, given that the polygraph test indicated that a lie was being told.
P(told truth|poly said lied) = 15/32
To get this " look only at the "poly said lied" row which has a total of 32
Then find the intersecting box for "told the truth" = 15
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Q8. If 1 subject is randomly selected, find the probability that he or she has a polygraph test indication that a lie was being told, given that the subject actually told the truth.
P(Poly said lied | person told truth)
Look at column for "told the truth" = 80
Find intersecting box "Poly said lied" = 15
P(...) = 15/80
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Cheers,
Stan H.
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