Book Image

Machine Learning with R Cookbook

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

Machine Learning with R Cookbook

By: Yu-Wei, Chiu (David Chiu)

Overview of this book

<p>The R language is a powerful open source functional programming language. At its core, R is a statistical programming language that provides impressive tools to analyze data and create high-level graphics.</p> <p>This book covers the basics of R by setting up a user-friendly programming environment and performing data ETL in R. Data exploration examples are provided that demonstrate how powerful data visualization and machine learning is in discovering hidden relationships. You will then dive into important machine learning topics, including data classification, regression, clustering, association rule mining, and dimension reduction.</p>
Table of Contents (21 chapters)
Machine Learning with R Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Resources for R and Machine Learning
Dataset – Survival of Passengers on the Titanic
Index

Performing cross-validation with the bagging method


To assess the prediction power of a classifier, you can run a cross-validation method to test the robustness of the classification model. In this recipe, we will introduce how to use bagging.cv to perform cross-validation with the bagging method.

Getting ready

In this recipe, we continue to use the telecom churn dataset as the input data source to perform a k-fold cross-validation with the bagging method.

How to do it...

Perform the following steps to retrieve the minimum estimation errors by performing cross-validation with the bagging method:

  1. First, we use bagging.cv to make a 10-fold classification on the training dataset with 10 iterations:

    > churn.baggingcv = bagging.cv(churn ~ ., v=10, data=trainset, mfinal=10)
    
  2. You can then obtain the confusion matrix from the cross-validation results:

    > churn.baggingcv$confusion
                   Observed Class
    Predicted Class  yes   no
                no   100 1938
                yes  242   35
    
  3. Lastly, you...