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

Performing correlations and multivariate analysis


To analyze the relationship of more than two variables, you would need to conduct multivariate descriptive statistics, which allows the comparison of factors. Additionally, it prevents the effect of a single variable from distorting the analysis. In this recipe, we will discuss how to conduct multivariate descriptive statistics using a correlation and covariance matrix.

Getting ready

Ensure that mtcars has already been loaded into a DataFrame within an R session.

How to do it...

Perform the following steps:

  1. Here, you can get the covariance matrix by inputting the first three variables in mtcars to the cov function:
        > cov(mtcars[1:3])
        Output:
                   mpg       cyldisp
        mpg  36.324103    -9.172379  -633.0972
        cyl  -9.172379     3.189516   199.6603
        disp -633.097208 199.660282 15360.7998
  1. To obtain a correlation matrix of the dataset, we input the first three variables of mtcarsto the cor function:
...