Suppose that a newly-developed rapid eld test for Type II diabetes has the follow- ing properties. (During test development, these properties were veried with more extensive testing.)

P (test indicates Type II diabetes | person actually has Type II diabetes)=0.90

P (test indicates Type II diabetes | person actually does not have Type II diabetes)=0.05

Suppose that 20% of individuals in a certain population have Type II diabetes.

B. Find the probability that a person really does have Type II diabetes given the test indicates that the person has Type II diabetes. Explain how you got the answer; give the formula and show intermediate steps.

Stuck on if B requires Bayes theorem calculation or general multiplication rule.