Discovering Knowledge in Data: An Introduction to Data Mining, 2nd Edition

AppendixData Summarization and Visualization

1. Part 1 Summarization 1: Building Blocks of Data Analysis
2. Part 2 Visualization: Graphs and Tables for Summarizing and Organizing Data
3. Part 3 Summarization 2: Measures of Center, Variability, and Position
4. Part 4 Summarization and Visualization of Bivariate Relationships

Here, we present a very brief review of methods for summarizing and visualizing data. For deeper coverage, please see Discovering Statistics, by Daniel Larose (second edition, W.H. Freeman, New York, 2013).

Part 1 Summarization 1: Building Blocks of Data Analysis

• Descriptive statistics refers to methods for summarizing and organizing the information in a data set. Consider Table A.1, which we will use to illustrate some statistical concepts.

  Table A.1 Characteristics of 10 loan applicants

  Applicant	Marital Status	Mortgage	Income ($)	Income Rank	Year	Risk
  1	Single	y	38,000	2	2009	Good
  2	Married	y	32,000	7	2010	Good
  3	Other	n	25,000	9	2011	Good
  4	Other	n	36,000	3	2009	Good
  5	Other	y	33,000	4	2010	Good
  6	Other	n	24,000	10	2008	Bad
  7	Married	y	25,100	8	2010	Good
  8	Married	y	48,000	1	2007	Good
  9	Married	y	32,100	6	2009	Bad
  10	Married	y	32,200	5	2010	Good

• The entities for which information is collected are called the elements. In Table A.1, the elements are the 10 applicants. Elements are also called cases or subjects.
• A variable is a characteristic of an element, which takes on different values for different elements. The variables in ...