Question

Assume that the chances of a patient having a heart attack is 40%. Assuming that a meditation and yoga course reduces the risk of heart attack by 30% and prescription of certain drug reduces its chance by 25%. 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. Interpret the result and state which of the above stated methods is more beneficial for the patient.

Answer 1

 

 

 

Let A, E₁, and E₂ respectively denote the events that a person has a heart attack, the selected person followed the course of yoga and meditation, and the person adopted the drug prescription.

`therefore P(A)=0.40`

`P(E_1)=P(E_2)=1/2`

`P(A|E_1)=0.40xx0.70=0.28P(A|E_2)=0.40xx0.75=0.30`

Probability that the patient suffering a heart attack followed a course of meditation and yoga is given by `P (E1|A).`

`P(E_1|A)=(P(E_1)P(A|E_1))/(P(E_1)P(A|E_1)+P(E_2)P(A|E_2))`

`=(1/2xx0.28)/(1/2xx0.28+1/2xx0.30)`

`=14/29`

Let us calculate `P(E_2|A)`

`P(E_2|A)=(P(E_2)P(A|E_2))/(P(E_1)P(A|E_1)+P(E_2)P(A|E_2))`

`=(1/2xx0.30)/(1/2xx0.28+1/2xx0.30)`

`=15/29`

Since  `P(E_1|A)<  P(E_2|A) ` the course of yoga and meditation is more beneficial for a person having chances of heart attack.