You now have several ways to examine a fitted model, but the business question still determines which evidence belongs in the answer. These tasks combine the unit skills on fresh fictional records. Read each requested partition, metric and output name before writing a cell. The first tasks isolate the calculation; later tasks combine it with the reporting decision or a boundary case. You will receive no new method here. Keep training, validation and test responsibilities separate, preserve the positive label, and let the result explain the decision. Reusing a familiar function on the wrong rows can produce a plausible number that answers a different question.