a test has been developed to detect a articular type of arthritis in individuals over the age of 50. Approximately 10% of persons above the age has this type of arthritis. The proposed test was given to individuals within this age group with confirmed arthritis of that type and correct result was obtained in 85% of the cases. When the same test was given to the persons of the age group known to be free of this particular type of arthritis, 4 % were reported with this disease. What is the probability that the individual has the disease when the test indicates its presence?