A laboratory blood test is 99`%` effective in detecting a certain disease when it is infact,present. However result for `0.5% `of the healthy person tested (i.e.,if a healthy person is tested,then with probability 0.005, the test will imply be has the disease). If `0.1%` of the population actually has the disease,what is the probability that a person has the disease given taht his test result is positive?

Suppose that the reliability of a HIV test is speciflẹd as follows: Of people having HIV '90 %' of the test detect the disease but '10 %' go undetected. Of people free of HIV, '99 %' of the test are judged HIV-ive but '1 %' are diagnosed as showing HIV+ịve. From a large population of which only '0.1 %' have HIV, one person is selected at random, given the HIV, test, and the pathologist reports him/her as HIV+ive. What is the probatility that the person actually has HIV?