exploring, displaying, and examining data

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© 2006 The McGraw-Hill Companies, Inc., All Rights Reserved.

McGraw-Hill/Irwin

Chapter 17Chapter 17

Exploring, Exploring, Displaying, and Displaying, and Examining DataExamining Data

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Learning Objectives

Understand . . .• exploratory data analysis techniques provide

insights and data diagnostics by emphasizing visual representations of the data

• how cross-tabulation is used to examine relationships involving categorical variables, serves as a framework for later statistical testing, and makes an efficient tool for data visualization and later decision-making

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Exploratory Data Analysis

• This Booth Research Services ad suggests that the researcher’s role is to make sense of data displays

• Great data exploration and analysis delivers insight from data

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Data Analysis

ConfirmatoryExploratory

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Exhibit 17-1 Data Exploration, Examination, and Analysis in the Research Process

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Exhibit 17-2 Frequency of Ad Recall

Value Label Value Frequency Percent Valid Cumulative Percent Percent

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Exhibit 17-3 Pie Chart

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Exhibit 17-3 Bar Chart

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Exhibit 17-4 Frequency Table

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Exhibit 17-5 Histogram

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Exhibit 17-6 Stem-and-Leaf Display

5

6

7

8

9

10

11

12

13

14

15

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21

455666788889

12466799

02235678

02268

24

018

3

1

06

3

36

3

6

8

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Exhibit 17-7 Pareto Diagram

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Exhibit 17-8 Boxplot Components

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Exhibit 17-9 Diagnostics with Boxplots

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Exhibit 17-10 Boxplot Comparison

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Mapping

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Digital Camera Map

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Exhibit 17-11 SPSS Cross-Tabulation

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Exhibit 17-12 Percentages in Cross-Tabulation

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Guidelines for Using Percentages

Averaging percentagesAveraging percentages

Use of too large percentagesUse of too large percentages

Using too small a baseUsing too small a base

Percentage decreases can never exceed 100%

Percentage decreases can never exceed 100%

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Exhibit 17-13 Cross-Tabulation with Control and Nested

Variables

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Exhibit 17-14 AID Example

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Key Terms

• Automatic interaction detection (AID)

• Boxplot• Cell• Confirmatory data

analysis• Contingency table• Control variable• Cross-tabulation• Exploratory data

analysis (EDA)

• Five-number summary• Frequency table• Histogram• Interquartile range (IQR)• Marginals• Nonresistant statistics• Outliers• Pareto diagram• Resistant statistics• Stem-and-leaf display