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What is cross-validation?
Updated May 17, 2026
Short answer
Cross-validation evaluates model performance by splitting data into multiple folds.
Deep explanation
It reduces variance in evaluation by training and testing on different subsets of data repeatedly.
Real-world example
Used in medical diagnosis models for robust validation.
Common mistakes
- Using cross-validation after test set evaluation.
Follow-up questions
- What is k-fold cross-validation?
- Why use cross-validation?