I don’t understand, even Reuters is giving random numbers: A third of those whose watches detected an irregular pulse were confirmed to have atrial fibrillatio

I don’t understand, even Reuters is giving random numbers: A third of those whose watches detected an irregular pulse were confirmed to have atrial fibrillation using the ECG technology, researchers said. Some 84 percent of the irregular pulse notifications were later confirmed to have been AF episodes, data showed. What is it then, 1/3 or 4/5?