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

12.7 PERFORMING PCA WITH k = 4

Figure 12.10 shows the resulting (i) unrotated and (ii) rotated component matrices for extracting three components. Let us examine the rotated matrix first in Figure 12.10b. Note that the component weights less than 0.5 have been suppressed, to enhance interpretability. The first principal component (RC1 for Rotated Component 1) is a combination of Different Items Purchased and Purchase Visits, which are positively correlated with each other, since their component weights have the same sign. Components can contain combinations of predictors that are either positively or negatively correlated with each other. Had exactly one of the component weights been negative, then that would have been an indication that Different Items Purchased and Purchase Visits were negatively correlated. The remaining principal components are “singletons,” containing only a single predictor each.

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figure 12.10 (a) component weights with no rotation, from r. (b) component...