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

4.2 BAR GRAPHS WITH RESPONSE OVERLAY

We can use bar graphs with a response overlay for exploring the relationship between a categorical predictor and the target variable. Figure 4.1 shows a bar graph of previous_outcome with an overlay of the target response. Previous_outcome refers to the result of a previous marketing campaign with this same customer, with most customers not having had such a previous experience.

Graph of Previous_outcome vs. count displaying horizontal stacked bars for success, nonexistent, and failure (top–bottom). The highest bar is nonexistent. The shades represent yes and no.

Figure 4.1 Bar graph from R of previous_outcome with response overlay.

Clearly, most customers did not have any previous marketing experience with the company (variable value nonexistent). In general, (non‐normalized) bar graphs are useful for showing the distribution of the values of the categorical variable. However, it is not clear which category has the greater proportion of responders. Nonexistent has the most responders but it also has the most nonresponders.

To clarify situations like these, we may obtain a normalized bar graph, which equalizes the length...