SOLUTION: It has been estimated that eighty percent of people with coronoary disease have chest pain syptom and twenty-five percent of people without the disease have chest pain symptoms. A

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Question 14613: It has been estimated that eighty percent of people with coronoary disease have chest pain syptom and twenty-five percent of people without the disease have chest pain symptoms. A person visits a doctor with chest pain symptom, what are the probabilities of the following events?
a) the person has coronary heart disease
b)the person does not have coronary disease.
I have just started my module on probability, I know this maybe pretty basic stuff, but would appreciate any help that will make it easier for me to understand the subject,thanks in advance.

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
It has been estimated that eighty percent of people with coronoary disease have chest pain syptom and twenty-five percent of people without the disease have chest pain symptoms. A person visits a doctor with chest pain symptom, what are the probabilities of the following events?
a) the person has coronary heart disease
Looks like a Bayes Problem:
Let "D" mean "has coronary disease"; Let "p" means "has pain".
P(D|P) = P(D and P)/[P(P and D) + P(P and not D)
= 0.80/(0.80 + 0.25) = 0.8/1.05 = 0.762
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b)the person does not have coronary disease.
Also, looks like a Bayes Problem.
P(not D |Pain) = P(not D and Pain)/[P(not D and Pain) + P(not D and not Pain)
=0.25/[0.25+0.20) = 0.556
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Cheers,
Stan H.