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?