A boiler-lockout alarm is quiet on 98 shifts out of 100. A dummy model that always predicts quiet is 98 percent accurate and never catches a lockout. Which statement should the plant trust?
Select an answer to reveal the explanation.
Short Explanation
Think of a smoke alarm that is right every quiet night and never rings on a fire. 98 percent quiet shifts make an always-quiet dummy look like a genius. Accuracy alone lies when one class owns the room.
Full Explanation
Accuracy counts every correct quiet shift, so a model that never predicts lockout can look excellent while missing every event that matters. That is why accuracy alone is misleading on an imbalanced label. High accuracy here is not proof of readiness and is not the only usable metric. Overfitting is memorizing training quirks, not the same thing as a high score on a dummy always-quiet rule.