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

10.3 AN APPLICATION OF k‐MEANS CLUSTERING

We apply the k‐means clustering algorithm to the white_wine_training and the white_wine_test data sets. These data sets are adapted from the Wine Quality data set at UCI.3The data consist of chemical and quality characteristics of a collection of Portuguese white wines. The predictors are alcohol and sugar. The target variable is quality, a measure of how good the wine is, according to a professional taster. When constructing clusters, it is important to not include the target variable as an input to the clustering algorithm. Doing so would bias the results if we later use the clusters to predict the target. It is also important to standardize or normalize all the predictors, so that the greater variability of one predictor does not dominate the cluster construction process.

Now, the k‐means algorithm requires the analyst to specify the desired number of clusters. For simplicity, we specify k = 2 clusters and proceed to apply...