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Hands-On Ensemble Learning with R

You're reading from   Hands-On Ensemble Learning with R A beginner's guide to combining the power of machine learning algorithms using ensemble techniques

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Product type Paperback
Published in Jul 2018
Publisher Packt
ISBN-13 9781788624145
Length 376 pages
Edition 1st Edition
Languages
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Author (1):
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Prabhanjan Narayanachar Tattar Prabhanjan Narayanachar Tattar
Author Profile Icon Prabhanjan Narayanachar Tattar
Prabhanjan Narayanachar Tattar
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Table of Contents (15) Chapters Close

Preface 1. Introduction to Ensemble Techniques FREE CHAPTER 2. Bootstrapping 3. Bagging 4. Random Forests 5. The Bare Bones Boosting Algorithms 6. Boosting Refinements 7. The General Ensemble Technique 8. Ensemble Diagnostics 9. Ensembling Regression Models 10. Ensembling Survival Models 11. Ensembling Time Series Models 12. What's Next?
A. Bibliography Index

Why does boosting work?

The Adaptive boosting algorithm section in the previous chapter contained m models, classifiers Why does boosting work?, n observations and weights, and a voting power that is determined sequentially. The adaptation of the adaptive boosting method was illustrated using a toy example, and then applied using specialized functions. When compared with the bagging and random forest methods, we found that boosting provides the highest accuracy, which you may remember from the results in the aforementioned section in the previous chapter. However, the implementation of the algorithm does not tell us why it was expected to perform better.

We don't have a universally accepted answer on why boosting works, but according to subsection 6.2.2 of Berk (2016), there are three possible explanations:

  • Boosting is a margin maximizer
  • Boosting is a statistical optimizer
  • Boosting is an interpolator

But what do these actually mean? We will now cover each of these points one by one. The margin for an observation...

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