What is the probability that the disease is resent given tha

What is the probability that the disease is resent given that the test is positive? What is the probability that the disease is not present given that the test is negative? Without making any changes to the test, what can be done to improve the accuracy of the testing procedure to determine that a patient either has or doesn\'t have the disease?

Solution

a) Prob that the disease is present given test is positive

= P(disease present and test positive)/Prob (test positive) (By definition of condl probability)

= 25/39 = 0.6410

b) Prob that disease is not present given test is negative = 78/96=0.8125

c) The Test positive for negative persons should be reduced to bare minimum and similarly test negative for positive persons should be strictly 0 as this is more dangerous misguidance.