7. Ensemble Methods – Bagging, Boosting, and Stacking
Ensemble methods collectively enhance predictive performance by leveraging the outputs of multiple models. Techniques like Bagging, Boosting, and Stacking each offer distinct strategies to improve model accuracy and increase stability, particularly for complex datasets. Understanding the strengths and weaknesses of these ensemble approaches is crucial for applying them effectively in various domains.
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What we have learnt
- Ensemble methods combine multiple models to create stronger predictive capabilities.
- Bagging improves stability and reduces variance, while Boosting reduces both bias and variance.
- Stacking leverages multiple model predictions through a meta-learner for optimal performance.
Key Concepts
- -- Ensemble Methods
- Techniques that combine multiple models to improve performance beyond what individual models can achieve.
- -- Bagging
- Bootstrap Aggregation; it involves averaging predictions from multiple model instantiations trained on bootstrapped datasets.
- -- Boosting
- A sequential ensemble technique that allows subsequent models to focus on correcting errors of the previous models.
- -- Stacking
- Combines multiple varied model outputs through a meta-model, learning the best way to integrate these predictions.
- -- Random Forest
- A specific algorithm leveraging bagging, used primarily with decision trees, to enhance predictive power.
- -- AdaBoost
- An adaptive boosting technique that adjusts weights for incorrectly classified instances to improve model accuracy across rounds.
- -- XGBoost
- An optimized implementation of gradient boosting that includes regularization techniques and improves speed and performance.
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