Count Correct Predictions on Held-Out Cases
Divide correct predictions by all evaluated cases when calculating this test-set accuracy.
About 18 minutes, plus any extended practice
Supplied materials
- Paper and pencil; answers may also be spoken or typed.
- All cases, labels, numbers and rules are supplied on this page. No real account, private information or purchase is needed.
Learn the idea
Held-out cases are kept separate from fitting a model. Comparing predictions with their supplied labels counts correct and incorrect results. The result describes this test set; it does not guarantee performance on new populations or future data. Keeping the denominator visible prevents inflated summaries.
Divide correct predictions by all evaluated cases when calculating this test-set accuracy. Do not discard wrong predictions from the denominator.
Use this supplied case: Held-out fictional test: 3 predictions correct out of 4. Accuracy percentage? The task is to connect the given information to the computing idea. Write a short evidence trail so another learner can reproduce your choice. The simplified case describes the stated model, not every real system.
- Represent the supplied worked case with a labeled drawing, table or short trace.
- Divide correct predictions by all evaluated cases when calculating this test-set accuracy.
- Explain why the worked answer fits and why one alternative does not.
- Try the new check and practice cases; revisit the stated rule if your evidence does not match.
See the method in action
The held-out test has 3 correct predictions among 4 labeled cases. Divide 3 by 4 to get 0.75, then multiply by 100 to report 75%. All four cases stay in the denominator, including the incorrect prediction. The result describes this supplied test set rather than all future objects; removing the error would inflate the reported evidence. No real learner information or actual model training is needed.
Check your reasoning
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Helpful tips
- Divide correct predictions by all evaluated cases when calculating this test-set accuracy.
- Do not discard wrong predictions from the denominator.
See the answer and explanation
80%
Using the supplied inputs: ((100*4)/5) = 80.0. Divide correct predictions by all evaluated cases when calculating this test-set accuracy. Do not discard wrong predictions from the denominator.
Take it further
New held-out test:11 correct of 20 cases. Expected:55%accuracy for that set. Do not remove the nine incorrect cases from the denominator.
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More practice: try new cases
Choose an answer for each problem. Explain your method on paper, then use the feedback to decide what to revisit.
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