Book Image

Data Analysis Using SQL and Excel - Second Edition

By : Gordon S. S. Linoff
Book Image

Data Analysis Using SQL and Excel - Second Edition

By: Gordon S. S. Linoff

Overview of this book

Data Analysis Using SQL and Excel, 2nd Edition shows you how to leverage the two most popular tools for data query and analysis—SQL and Excel—to perform sophisticated data analysis without the need for complex and expensive data mining tools. Written by a leading expert on business data mining, this book shows you how to extract useful business information from relational databases. You'll learn the fundamental techniques before moving into the "where" and "why" of each analysis, and then learn how to design and perform these analyses using SQL and Excel. Examples include SQL and Excel code, and the appendix shows how non-standard constructs are implemented in other major databases, including Oracle and IBM DB2/UDB. The companion website includes datasets and Excel spreadsheets, and the book provides hints, warnings, and technical asides to help you every step of the way. Data Analysis Using SQL and Excel, 2nd Edition shows you how to perform a wide range of sophisticated analyses using these simple tools, sparing you the significant expense of proprietary data mining tools like SAS.
Table of Contents (18 chapters)
Free Chapter
1
Foreword
17
EULA

The Best-Fit Line

The simplest case of linear regression has one input variable and one target variable. This case is best illustrated with scatter plots, making it readily understandable visually and giving rise to the name “best-fit line.”

Tenure and Amount Paid

The first example is for a set of customers in a subscription-based business, comparing the tenure of each customer with the total amount the customer has paid. The longer customers remain active, the more they pay—an evident relationship between the two values.

Figure 12-1

Image described by surrounding text.

Figure 12.1: This chart shows the best-fit line for a set of data points showing the relationship between customers’ tenures and the amount they have paid.

One way to use the best-fit line is to estimate how much a customer would pay if he or she survived to a given tenure. A typical customer with tenure of 360 days should pay about $192.30. This amount might influence acquisition budgets.

This simple example shows the virtues...