Let,
X1 = Patient that is Critical
X2 = Patient that is Serious
X3 = Patient that is Stable
D = Dead Patient
V = Survived Patient
Using Baye's Formula:
Let,
P(X2, V) = the probability that the patient who survived was categorized as serious upon arrival.
[tex]\text{ P (X}_i,V)\text{ = }\frac{P(X_i)\text{ x }P(X_i,V)}{P(X_1)\text{ x }P(X_1,V)\text{ + }P(X_2)\text{ x }P(X_2,V)\text{ + }\ldots\text{ +}P(X_n)\text{ x }P(X_n,V)}[/tex]We are given,
P(X1) = 0.12
P(X2) = 0.27
P(X3) = 1 - (0.12 + 0.27) = 0.61
P(X1,V) = 1 - P(X1,D) = 1 - 0.43 = 0.57
P(X2,V) = 1 - P(X2,D) = 1 - 0.26 = 0.74
P(X3,V) = 1 - P(X3,D) = 1 - .05 = 0.95
We now solve for the probability that the patient who survived was categorized as serious upon arrival,
[tex]P(X_2,V)\text{ = }\frac{(0.27)(0.74)}{(0.12)(0.57)\text{ + (0.27)(0.74) + (0.61)(0.95)}}\text{ =}\frac{0.1998}{0.8477}[/tex][tex]P(X_2,V)\text{ = 0.2356965908 }\approx\text{ 0.}2357[/tex]The probability that the patient who survived was categorized as serious upon arrival is 0.2357.