Why You Hold Out a Test Set
Estimating performance on unseen data.
The Real Question
A model that memorizes your data looks brilliant on it. The real question is how it does on data it has never seen.
Hold Some Data Back
So you set aside part of your data and never train on it. This locked-away slice is your test set, kept for the very end.
All lessons in this course
- Why You Hold Out a Test Set
- train_test_split Done Right
- K-Fold Cross-Validation
- Stop Data Leakage Before It Starts