Implement linear regression from scratch
Last updated: October 23, 2025
Quick Overview
Write a clean implementation of k-means without using ML libraries.
Notion
October 23, 20258
10
242 solved
Write a clean implementation of k-means without using ML libraries.
This ML question from Notion's Phone Screen goes beyond textbook definitions. The interviewer wants to see how you reason about model selection, evaluation metrics, and the practical challenges of deploying ML in production.
What the Interviewer Expects
- Explain the concept clearly with intuitive examples
- Discuss when and why to use this technique
- Identify common pitfalls and how to avoid them
- Compare with alternative approaches at a high level
Key Topics to Cover
How to Approach This
- Understand the bias-variance trade-off. High training accuracy but low test accuracy signals overfitting.
- Choose evaluation metrics carefully based on the problem. Accuracy alone is often insufficient.
- Feature engineering is often more impactful than model selection.
- Know when to use tree-based models (tabular data) vs neural networks (unstructured data).
- Handle class imbalance with SMOTE, class weights, or appropriate loss functions.
Possible Follow-up Questions
- What regularization technique would you use and why?
- How would you handle a highly imbalanced dataset?
- How would you detect and handle concept drift?
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Explore ML Interview PrepSample Answer
Core Concept Explanation
Start with a clear, intuitive explanation of the concept. Use analogies when helpful. Then go deeper into the mathematical foundations: **Key Intuiti...
Practical Application
**When to use**: Describe the scenarios where this technique is most effective. What data characteristics favor it? **When NOT to use**: Common pitfa...
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