7. ANNEX

Q1. It is known that in a certain city one out of every 100 citizens is a tubercular person. A test was administered to a citizen. When a person is tubercular the test gives a positive result in 97% of cases. When he/she is not tubercular, only 0.01% of the cases give positive results. If the test is positive for these people, what is the probability that he/she is tubercular?

Q2. A diagnostic test for diabetes has an FPC of 4% and an FNC of 5%. If the prevalence of diabetes in a town is 7%, what is the probability that a person is diabetic if his/ her test was positive? What is the probability that a person is not diabetic if his/her test was negative?

Q3. A diagnostic test for uterine cancer has a false positive coefficient of 0.05 and false negative of 0.01. A woman with a pre-test probability of 0.15 of having the disease has a negative result in her test. Calculate the probability that she is not ill?

Q4. The tuberculin test can test whether a person is infected by tuberculosis or not. The sensitivity and specificity of the test is very high, 0.97 and 0.98 respectively. If in a certain town there is a very high proportion of false positives, exactly 0.9, calculate the prevalence of the disease.