Book Image

Learning Predictive Analytics with R

By : Eric Mayor
Book Image

Learning Predictive Analytics with R

By: Eric Mayor

Overview of this book

This book is packed with easy-to-follow guidelines that explain the workings of the many key data mining tools of R, which are used to discover knowledge from your data. You will learn how to perform key predictive analytics tasks using R, such as train and test predictive models for classification and regression tasks, score new data sets and so on. All chapters will guide you in acquiring the skills in a practical way. Most chapters also include a theoretical introduction that will sharpen your understanding of the subject matter and invite you to go further. The book familiarizes you with the most common data mining tools of R, such as k-means, hierarchical regression, linear regression, association rules, principal component analysis, multilevel modeling, k-NN, Naïve Bayes, decision trees, and text mining. It also provides a description of visualization techniques using the basic visualization tools of R as well as lattice for visualizing patterns in data organized in groups. This book is invaluable for anyone fascinated by the data mining opportunities offered by GNU R and its packages.
Table of Contents (23 chapters)
Learning Predictive Analytics with R
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Exercises and Solutions
Index

Distance measures


Partitioning clustering algorithms iteratively define k cluster centers and assign cluster membership (or the probability of group membership) to cases based on distances between the case and the cluster. Agglomerative clustering algorithms also create clusters based on distances, starting with each individual belonging to a separate cluster and the grouping clusters two by two. The k-nearest neighbors algorithm also uses distance measures.

Consider only one attribute, for instance the height of individuals. The distance of someone measuring 180 cm and someone measuring 170 cm will be 10 on this sole dimension considering the algebraic difference between the two measures as our distance metric. Things get a little more complicated when we add more attributes, such as weight (we will not consider variable scaling here). Let's say the first individual is clearly overweight (90 kg), and the second has a normal weight (80 kg). Considering only the sum of the difference between...