A new medical procedure has been shown to be effective in the early detection of a disease. The probability the test is positive for a person having the disease is 0.9. The probability the test is negative for a person NOT having the disease 0.85. The probability of this disease in the general population is 0.0002. If a person takes the test and the result is positive, what is the probability that this person has the disease? (Show calculations with adequate precision)