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Machine Learning

What are training, validation and test data?

A model needs evaluation on data it did not learn from.

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01 · Understand the idea

In simple words

When preparing for an exam, you study examples, use practice tests to improve and finally take an unseen exam. ML evaluation uses a similar separation. Training fits the model, validation guides your choices and testing checks the final design on held-out examples. The separation helps make your score more honest.

Two useful terms

Training set: examples used to fit a model. Held-out data: examples kept separate from fitting.

Build your understanding

A model needs evaluation on data it did not learn from. Training data fits parameters, validation data supports model choices and test data provides a final held-out check. The split must reflect how the system will be used: time, users and groups can create dependencies between rows.

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