Syllabus Map

• Study map: Syllabus Study Map

Core Idea

• Evaluation requires representative sampling and strict holdout discipline.

Practical Notes

Keep test data untouched until final evaluation.

• Using test feedback during tuning causes leakage.

Stratify when class imbalance is present.

• Preserves class proportions across splits.

Why This Matters for ML

• Reliable generalization estimates require clean train/validation/test separation.
• Sampling strategy affects class balance, metric stability, and fairness of comparisons.
• Leakage from improper splits can invalidate reported performance.
• Cross-validation and stratification decisions are rooted in these fundamentals.