Book Image

Data Science Using Python and R

By : Chantal D. Larose, Daniel T. Larose
Book Image

Data Science Using Python and R

By: Chantal D. Larose, Daniel T. Larose

Overview of this book

Data science is hot. Bloomberg named a data scientist as the ‘hottest job in America’. Python and R are the top two open-source data science tools using which you can produce hands-on solutions to real-world business problems, using state-of-the-art techniques. Each chapter in the book presents step-by-step instructions and walkthroughs for solving data science problems using Python and R. You’ll learn how to prepare data, perform exploratory data analysis, and prepare to model the data. As you progress, you’ll explore what are decision trees and how to use them. You’ll also learn about model evaluation, misclassification costs, naïve Bayes classification, and neural networks. The later chapters provide comprehensive information about clustering, regression modeling, dimension reduction, and association rules mining. The book also throws light on exciting new topics, such as random forests and general linear models. The book emphasizes data-driven error costs to enhance profitability, which avoids the common pitfalls that may cost a company millions of dollars. By the end of this book, you’ll have enough knowledge and confidence to start providing solutions to data science problems using R and Python.
Table of Contents (20 chapters)
Free Chapter
1
ABOUT THE AUTHORS
17
INDEX
18
END USER LICENSE AGREEMENT

12.3 IDENTIFYING MULTICOLLINEARITY USING VARIANCE INFLATION FACTORS

However, suppose we did not check for the presence of correlation among our predictors, and went ahead and performed the regression anyway. Is there some way that the regression results can warn us of the presence of multicollinearity? The answer is yes: We may ask for the variance inflation factors (VIFs) to be reported.

The VIF for the ith predictor is given by:

equationVIFi=11Ri2--

where imagesRi2--R2 value obtained by regressing xi on the other predictor variables. Note that imagesRi2--xi is highly correlated with the other predictors, thus making VIFi large.

A rough rule of thumb for interpreting the value of the VIF is to consider VIFi ≥ 5 to be an indicator of moderate multicollinearity, and to consider VIFi ≥ 10 to be an indicator of severe multicollinearity. A VIF of five corresponds to imagesRi2--VIFi = 10 corresponds to imagesRi2--

For the regression of nutritional rating on fiber, potassium...