Book Image

Hands-On Ensemble Learning with R

By : Prabhanjan Narayanachar Tattar
Book Image

Hands-On Ensemble Learning with R

By: Prabhanjan Narayanachar Tattar

Overview of this book

Ensemble techniques are used for combining two or more similar or dissimilar machine learning algorithms to create a stronger model. Such a model delivers superior prediction power and can give your datasets a boost in accuracy. Hands-On Ensemble Learning with R begins with the important statistical resampling methods. You will then walk through the central trilogy of ensemble techniques – bagging, random forest, and boosting – then you'll learn how they can be used to provide greater accuracy on large datasets using popular R packages. You will learn how to combine model predictions using different machine learning algorithms to build ensemble models. In addition to this, you will explore how to improve the performance of your ensemble models. By the end of this book, you will have learned how machine learning algorithms can be combined to reduce common problems and build simple efficient ensemble models with the help of real-world examples.
Table of Contents (17 chapters)
Hands-On Ensemble Learning with R
Contributors
Preface
12
What's Next?
Index

What is ensemble diagnostics?


The power of ensemble methods was demonstrated in the preceding chapters. An ensemble with decision trees forms a homogeneous ensemble, and this was the main topic of Chapter 3, Bagging, to Chapter 6, Boosting Refinements. In Chapter 1, Introduction to Ensemble Techniques, and Chapter 7, The General Ensemble Technique, we had a peek at stacked ensembles. A central assumption in an ensemble is that the models are independent of one another. However, this assumption is seldom true, and we know that the same data partition is used over and over again. This does not mean that ensembling is bad; we have every reason to use the ensembles while previewing the concerns in an ensemble application. Consequently, we need to see how close the base models are to each other and overall in their predictions. If the predictions are close to each other, then we might need those base models in the ensemble. Here, we will build logistic regression, Naïve Bayes, SVM, and a decision...