Q. 13  Assume that the chances of a patient having a heart attack is 40^{o}/_{o}. It is also assumed that a meditation and yoga course reduce the risk of heart attack by 30^{o}/_{o} and prescription of certain drug reduces its chances by 25^{o}/_{o}.At a time a patient can choose any one of the two options with equal probabilities. It is given that after going through one of the two options the patient selected at random suffers a heart attack. Find the probability that  the patient followed a course of meditation and yoga?

Answers (1)
S seema garhwal

    Let A,E1, E2 respectively denote the event that a person has a heart break, selected person followed the course of yoga and meditation , and the person adopted

     the drug prescription.

    \therefore \, \, \, \, P(A)=0.40

\therefore \, \, \, \, P(E1)=P(E2)=\frac{1}{2}

P(A|E1)=0.40\times 0.70=0.28

P(A|E2)=0.40\times 0.75=0.30

the probability that the patient followed a course of meditation and yoga is P(E1,A)

                         P(E1,A)=\frac{P(E1).P(E1|A)}{P(E1).P(E1|A)+P(E2).P(E2|A)}

                        P(E1,A)=\frac{0.5\times 0.28}{0.5\times 0.28 + 0.5\times 0.30}

                                                 =\frac{14}{29}

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