SOLUTION: use this data.
subject actually told the truth and polygraph indicated truth 65
subject actually told the truth and polygraph indicate
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Question 74535: 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 funmath(2933) (Show Source): You can put this solution on YOUR website!
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.
The number of people who told a lie is x=3+17=20
The total number of people in the sample is n=100
P(x)=x/s
The probability of selecting a person who told a lie is:P(x)=x/n; 20/100=.20
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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.
The number of people who the polygraph test indicated a lie is x=15+17=32
n=100
The probability of selecting someone who the polygraph indicated was lying is:P(x)=x/n; 32/100=.32
:
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.
For "or" apply the addition rule: P(A or B)=P(A)+P(B)-P(AnB) (imagine n to be the union symbol)
P(someone told a lie)=.20 (refer to Q1)
P(polygraph indicated a lie)=.32
P(someone told a lie union the polygraph indicated a lie)=17/100=.17
P(someone told a lie "or" the polygraph indicated a lie)=.20+.32-.17=.35
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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.
P(someone told the truth)=(65+15)/100=80/100=.80
P(polygraph indicated truth)=(65+3)/100=68/100=.68
P(told the truth union polygraph indicated truth)=65/100=.65
P(someone told the truth "or" the polygraph indicated truth)=.80+.68-.65=.83
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Q5. If 2 diffrent subjects are randomly selected, find the probability that they both told the truth.
For "and" (implied by "both") use multiplication rule: P(A and B)=P(A)*P(B|A)
P(first one told the truth)=(65+15)/100=80/100=.80
P(the second one told the truth given that the first one did)=(80-1)/(100-1)=79/99=.79798
P(they both told the truth)=(.80)(.79798)=.638384 or about .64
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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.
This is done the same way as Q5, you should get .100202 or .10
Let me know if you don't.
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.
The number of people that told the truth and the polygraph indicated a lie is: x=15
The number that the polygraph indicated was lying: n=15+17=32
P(told the truth given that the polygraph indicated a lie)=15/32=.46875 or about .47
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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.
This is done the same way as Q7, you should get: .1875 or about .19
Let me know if you don't
Remember, I'm a human being. Double check everything. Let me know if you don't get the same thing I got.
:
Happy Calculating!!!!
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