Product defect probability tree

This probability tree separates a product's actual condition from the result of an inspection. A defective item can be found or missed, while a good item can be falsely rejected or pass. The branch probabilities describe how the inspection behaves within each condition. This is a useful structure for quality teams because it distinguishes the true state from the observed result. Add the proportion of defective products at the first split when you need overall probabilities, such as the chance that a rejected item was genuinely defective. The same pattern also applies to tests, alarms, and screening processes. It gives readers a concise reference they can reuse when discussing the result with colleagues.