Day 1 · Monday
From a question to a prediction you can trust
Before you trust a prediction, you need to know exactly what it was asked to do. Today we build that standard piece by piece, and then we apply it to a real claim.
By the end of today
You will be able to:
- frame a business question as a prediction task with a written contract;
- name the loss and the baseline that judge a prediction;
- explain why we split data into training, validation, and test sets;
- spot a feature that leaks information from after the prediction moment;
- say what a 90% accuracy figure does and does not show.
What we cover
- slides 5–11Part I: What machine learning isShort. Where these methods sit and what they estimate.
- slides 12–23Part II: The prediction contractWhat must be written down before anyone fits anything.
- slides 24–34Part III: Learning from dataLoss, baselines, and the three-way split.
- slides 35–51Part IV: The limitsLeakage, decayed models, and what a score can and cannot support.
Slides 52–57 are optional appendix material for students who want the full algebra.
Lecture materials
Review questions
Five questions open tomorrow's session.
- What baseline did the 90% model have to beat, and what was its value?
- A new column makes your validation score jump. What do you check first?
- Why may the test set be used only once?
- Accuracy 90.2% and recall 23.3% describe the same model. Explain how both can be true.
- Why does a high response probability alone not show that calling causes subscriptions?
Oxford · United Kingdom
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