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

PART 4: SUMMARIZATION AND VISUALIZATION OF BIVARIATE RELATIONSHIPS

  • A bivariate relationship is the relationship between two variables.
  • The relationship between two categorical variables is summarized using a contingency table, which is a crosstabulation of the two variables, and contains a cell for every combination of variable values (that is, for every contingency). Table A.5 is the contingency table for the variables mortgage and risk. The total column contains the marginal distribution for risk, that is, the frequency distribution for this variable alone. Similarly, the total row represents the marginal distribution for mortgage.
  • Much can be learned from a contingency table. The baseline proportion of bad risk is 2/10 = 20%. However, the proportion of bad risk for applicants without a mortgage is 1/3 = 33%, which is higher than the baseline; and the proportion of bad risk for applicants with a mortgage is only 1/7 = 1%, which is lower than the baseline. Thus, whether or not the applicant...