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

Apriori – basic concepts


There are some concepts about apriori that need to be understood before going further in this chapter: association rules, itemsets, support, confidence, and lift.

Association rules

An association rule is the explicit mention of a relationship in the data, in the form X => Y, where X (the antecedent) can be composed of one or several items. X is called an itemset. In what we will see, Y (the consequent) is always one single item. We might, for instance, be interested in what the antecedents of lemon are if we are interested in promoting the purchase of lemons.

Itemsets

Frequent itemsets are items or collections of items that occur frequently in transactions. Lemon is the most frequent itemset in the previous example, followed by cherry coke and chips. Itemsets are considered frequent if they occur more frequently than a specified threshold. This threshold is called minimal support. The omission of itemsets with support less than the minimal support is called support...