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

4.3 CONTINGENCY TABLES

To help quantify the relationship between a categorical predictor and the target, we can construct a contingency table, which is a cross‐tabulation of the two variables, and contains a cell for every combination of variable values (that is, for every contingency). Figure 4.4 contains a contingency table of previous_outcome with response. Note that the usual practice is to have the target variable representing the rows, with the predictor representing the columns. For EDA, it is also helpful to include the column percentages. Figure 4.5 contains the table with column percentages. Most customers had no previous marketing campaign (nonexistent), so note that 21,176 of these responded no while 2034 responded yes. Overall, note that the proportion of yes response is only 13.9% for failure and only 8.8% for nonexistent, but a very high 64% when the customer's previous marketing campaign was a success.

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Figure 4.4 Contingency table from R of previous_outcome...