This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
ECG was performed on a total of 700 subjects with complaints of acute chest pain. Of these, 520 patients had myocardial infarction. Calculate the positive predictive value of ECG is: MYOCARDIAL INFARCTION ECG PRESENT ABSENT TOTAL POSITIVE 416 9 425 NEGATIVE 104 171 275 TOTAL 520 180 700 
Select and explain. 
A. 40%, B. 55%, C. 95%, D. 98%
D: 98%
Answer: D: 98% 
Explanation: Positive predictive value=true positive/(true positive+ false positive) 416/425 x 100= 98% Ref: Medical biostatistics, 1st edition pg: 201