Technical Phone Screen: Cross-Validation
Task
You are interviewing for a Data Scientist role. Explain and reason about k-fold cross-validation.
Questions
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Describe the k-fold cross-validation procedure concisely.
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What are the trade-offs in choosing the number of folds k (bias–variance, compute, stability)?
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In what situations can cross-validation give misleading performance estimates? Discuss the roles of data leakage, temporal/ordered data, and class imbalance.