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Hands-On Machine Learning with scikit-learn and Scientific Python Toolkits

You're reading from   Hands-On Machine Learning with scikit-learn and Scientific Python Toolkits A practical guide to implementing supervised and unsupervised machine learning algorithms in Python

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Product type Paperback
Published in Jul 2020
Publisher Packt
ISBN-13 9781838826048
Length 384 pages
Edition 1st Edition
Languages
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Author (1):
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Tarek Amr Tarek Amr
Author Profile Icon Tarek Amr
Tarek Amr
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Table of Contents (18) Chapters Close

Preface 1. Section 1: Supervised Learning
2. Introduction to Machine Learning FREE CHAPTER 3. Making Decisions with Trees 4. Making Decisions with Linear Equations 5. Preparing Your Data 6. Image Processing with Nearest Neighbors 7. Classifying Text Using Naive Bayes 8. Section 2: Advanced Supervised Learning
9. Neural Networks – Here Comes Deep Learning 10. Ensembles – When One Model Is Not Enough 11. The Y is as Important as the X 12. Imbalanced Learning – Not Even 1% Win the Lottery 13. Section 3: Unsupervised Learning and More
14. Clustering – Making Sense of Unlabeled Data 15. Anomaly Detection – Finding Outliers in Data 16. Recommender System – Getting to Know Their Taste 17. Other Books You May Enjoy

Sampling the training data

"It's not denial. I'm just selective about the reality I accept."
- Bill Watterson

If the machine learning models were humans, they would have believed that the end justifies the means. When 99% of their training data belongs to one class, and their aim is to optimize their objective function, we cannot blame them if they focus on getting that single class right since it contributes to 99% of the solution. In the previous section, we tried to change this behavior by giving more weights to the minority class, or classes. Another strategy might entail removing some samples from the majority class or adding new samples to the minority class until the two classes are balanced.

Undersampling the majority class

"Truth, like gold, is to be obtained not by its growth, but by washing...
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