This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Screening, Subject name: Social & Preventive Medicine
[{'content': 'A test has a high false positive rate in a community. True is \nSelect and explain. \nA. High prevalence, B. Low prevalence, C. High sensitivity, D. High specificity', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The propoion of false-positive results among those who test positive is 1 minus the positive predictive value. False positive (discovery) rate = 1- positive predictive valueAs the disease prevalence increases, the positive predictive value increases. (PPV)As prevalence increase, PPV increase, False positive rate decrease.', 'role': 'assistant'}]