How many samples to trust a 3% false-merge rate?
Power & sample sizeMediumProblem. You want to estimate the graph's false-merge rate, which you believe is around 3%, tightly enough to detect a change to 4%. How many audited merges do you need — and why is a rare rate hard?
Before you reveal: say your answer out loud, as if you were in the real interview — get your reasoning across clearly first. There is no single correct answer: reading what the interviewer is really after and defending your own thinking is what makes an answer strong.