A doctor is called to see a sick child. The doctor has prior…
A doctor is called to see a sick child. The doctor has prior information that 90% of sick children in that neighborhood have the flu, while the other 10% are sick with measles. A well-known symptom of measles is a rash. Assume that the probability of having a rash if one has measles is 95%. However, occasionally children with flu also develop rash, and the probability of having a rash if one has flu is 8%. Upon examining the child, the doctor finds a rash. What is the probability that the child has flu?