A new test has been developed to determine whether a given student is overstressed.

A new test has been developed to determine whether a given student isoverstressed. This test is 95% accurate if the student is not overstressed, but only 85%accurate if the student is in fact overstressed. It is known that 99.5% of all studentsare overstressed. Given that a particular student tests negative for stress, what is theprobability that the test results are correct, and that this student is not overstressed?