Book Image

Machine Learning with R Cookbook, Second Edition - Second Edition

By : Yu-Wei, Chiu (David Chiu)
Book Image

Machine Learning with R Cookbook, Second Edition - Second Edition

By: Yu-Wei, Chiu (David Chiu)

Overview of this book

Big data has become a popular buzzword across many industries. An increasing number of people have been exposed to the term and are looking at how to leverage big data in their own businesses, to improve sales and profitability. However, collecting, aggregating, and visualizing data is just one part of the equation. Being able to extract useful information from data is another task, and a much more challenging one. Machine Learning with R Cookbook, Second Edition uses a practical approach to teach you how to perform machine learning with R. Each chapter is divided into several simple recipes. Through the step-by-step instructions provided in each recipe, you will be able to construct a predictive model by using a variety of machine learning packages. In this book, you will first learn to set up the R environment and use simple R commands to explore data. The next topic covers how to perform statistical analysis with machine learning analysis and assess created models, covered in detail later on in the book. You'll also learn how to integrate R and Hadoop to create a big data analysis platform. The detailed illustrations provide all the information required to start applying machine learning to individual projects. With Machine Learning with R Cookbook, machine learning has never been easier.
Table of Contents (21 chapters)
Title Page
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface

Introduction


Ensemble learning is a method for combining results produced by different learners into one format, with the aim of producing better classification results and regression results. In previous chapters, we discussed several classification methods. These methods take different approaches, but they all have the same goal, that is, finding an optimum classification model.

However, a single classifier may be imperfect, as it misclassify data in certain categories. As not all classifiers are imperfect, a better approach is to average the results by voting. In other words, if we average the prediction results of every classifier with the same input, we may create a superior model compared to using an individual method.

In ensemble learning, bagging, boosting, and random forest are the three most common methods:

  • Bagging is a voting method, which first uses Bootstrap to generate a different training set, and then uses the training set to make different base learners. The bagging method...