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

Understanding simple regression


In simple regression, we analyze the relationship between a predictor (the attribute we think to be the cause) and the criterion (the attribute we think is the consequence). There are two very important parameters (among others) that result from a regression analysis:

  • The intercept: This is the average value of the criterion when the predictor is 0, which is when the effect of the predictor is partialed out

  • The slope coefficient: This indicates by how many units, on average, the criterion changes (with reference to the intercept) when the predictor increases by one unit

Regression seeks to obtain the values that explain the relationship the best, but such a model only seldom reflects the relationship entirely. Indeed, measurement error, but also attributes that are not included in the analysis affect also the data. The residuals express the deviation of the observed data points to the model. Its value is the vertical distance from a point to the regression line...