question_answer 1)

A laboratory blood test is 99% effective in detecting a certain disease when it is in fact, present. However, the test also yields a false positive result for 0.5% of the healthy person tested. If 0.1% of the population actually has the disease, what is the probability that a person has the disease, given that his test result is positive ? 

Answer:

Let E1 and E2 are the events that a person has disease and the person has not disease.       Let A =event that test result is positive.                          and P(A/E1) =       Required probability = P(E1/A)