Book Image

Statistical Application Development with R and Python - Second Edition

Book Image

Statistical Application Development with R and Python - Second Edition

Overview of this book

Statistical Analysis involves collecting and examining data to describe the nature of data that needs to be analyzed. It helps you explore the relation of data and build models to make better decisions. This book explores statistical concepts along with R and Python, which are well integrated from the word go. Almost every concept has an R code going with it which exemplifies the strength of R and applications. The R code and programs have been further strengthened with equivalent Python programs. Thus, you will first understand the data characteristics, descriptive statistics and the exploratory attitude, which will give you firm footing of data analysis. Statistical inference will complete the technical footing of statistical methods. Regression, linear, logistic modeling, and CART, builds the essential toolkit. This will help you complete complex problems in the real world. You will begin with a brief understanding of the nature of data and end with modern and advanced statistical models like CART. Every step is taken with DATA and R code, and further enhanced by Python. The data analysis journey begins with exploratory analysis, which is more than simple, descriptive, data summaries. You will then apply linear regression modeling, and end with logistic regression, CART, and spatial statistics. By the end of this book you will be able to apply your statistical learning in major domains at work or in your projects.
Table of Contents (19 chapters)
Statistical Application Development with R and Python - Second Edition
Credits
About the Author
Acknowledgment
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface
Index

Techniques for exploratory analysis


We will be studying the following techniques:

  • The stem-and-leaf plot

  • Letter values

  • Data re-expression

  • Bagplot—a bivariate boxplot

  • Resistant line

  • Smoothing data

  • Median polish

The stem-and-leaf plot

The stem-and-leaf plot is considered as one of the seven important tools of Statistical Process Control (SPC); refer to Montgomery (2005). It is a bit similar in nature to the histogram plot.

The stem-and-leaf plot is an effective method of displaying data in a (partial) tree form. Here, each datum is split into two parts: the stem part and the leaf part. In general, the last digit of a datum forms the leaf part; the rest form the stem. Now, consider a datum 235. If the split criteria is the units place, the stem and leaf parts here will be respectively 23 and 5; if it is tens, then 2 and 3; and finally if it is hundreds, it will be 0 and 2. The left-hand side of the split datum is called the leading digits and the right-hand side the trailing digits.

In the next step,...