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

Measuring prediction performance using ROCR


A receiver operating characteristic (ROC) curve is a plot that illustrates the performance of a binary classifier system, and plots the true positive rate against the false positive rate for different cut points. We most commonly use this plot to calculate the area under curve (AUC) to measure the performance of a classification model. In this recipe, we will demonstrate how to illustrate an ROC curve and calculate the AUC to measure the performance of a classification model.

Getting ready

In this recipe, we will continue using the telecom churn dataset as our example dataset.

How to do it...

Perform the following steps to generate two different classification examples with different costs:

  1. First, you should install and load the ROCR package:

    > install.packages("ROCR")
    > library(ROCR)
    
  2. Train the svm model using the training dataset with a probability equal to TRUE:

    > svmfit=svm(churn~ ., data=trainset, prob=TRUE)
    
  3. Make predictions based on the...