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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)
      (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.
 
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