20 in 100 patients in a clinic have Clostrdium Difficile Infection (CDI). For the initial test a false positive rate is 0.3 (30% of patients without CDI will test positive). For the initial test a false negatives 0.15 (15% of patients without CDI will test negative). If a patient has an infection there is 85% chance that will test positive. Suppose a test is positive