Suppose that a patient can have a symptom (S) that can be caused by two different diseases (A and B). It is known that the variation of gene G plays a big role in the occurrence of disease A. The Bayes net and corresponding conditional probability tables for this situation are in Figure S13.29. 

a. Compute the joint probability P(+g, +a, +b, +s). 

b. What is the probability that a patient has disease A? 

c. What is the probability that a patient has disease A given that they have disease B? 

d. What is the probability that a patient has disease A given that they have symptom S and disease B? 

e. What is the probability that a patient has the disease-carrying gene variation G given that they have disease A? 

f. What is the probability that a patient has the disease-carrying gene variation G given that they have disease B?

Figure S13.29

Transcribed Image Text:

P(G) +g 0.1 90.9 P(AG) +9+a 1.0 +g-a 0.0 -9+a 0.1 -9-a 0.9 (G) A (S) B P(B) +b 0.4 -b 0.6 P(S A,B) +a+b+s 1.0 +a+b-s 0.0 +a-b+8 0.9 +a-b-8 0.1 -a+b+s 0.8 -a+b-8 0.2 -a-b+8 0.1 -a-b-8 0.9