SlideShare a Scribd company logo
1 of 23
CITOOLKIT
Box Plot
The Role of Box Plots in Comparing Multiple Data Sets
citoolkit.com
Definition
One of the best ways to analyze any process is to plot the data on a graph
or chart.
Box Plot 2
*
X
X
X
X
X
X
X
X
X
X
X
citoolkit.com
Definition
A box plot is a graph that shows the frequency of numeric data values.
Box Plot 3
Also referred to as a Box-and-
Whisker Plot as it displays the
data in a box-and-whiskers
format.
citoolkit.com
Applications
Mainly used to explore data as well as to present the data in an easy and
understandable manner.
Box Plot 4
Box plots are widely used in
statistics, process improvement,
scientific research, economics,
and in social and human sciences
citoolkit.com
Vertical vs. Horizontal
Box plots can be drawn either vertically or horizontally.
Box Plot 5
The length of the box plot indicates the spread of the data.
citoolkit.com
Characteristics
They provide a quick way for examining the central tendency and variation
present in the data.
Box Plot 6
* * Outliers are usually
plotted as asterisks
A wider range boxplot indicates more variability.
citoolkit.com
Characteristics
Box plots are useful when comparing between several data sets.
Box Plot 7
A B C D
In terms of central tendency and variability.
citoolkit.com
Characteristics
The same continuous data can be presented graphically using histograms
and box plots.
Box Plot 8
Mean
*
●
citoolkit.com
Characteristics
Less detailed than histograms and take up less space which make them
more practical when comparing multiple data sets.
Box Plot 9
citoolkit.com
Uses
Used to check if there is a significant difference in the process after
implementing process improvement.
Box Plot 10
BEFORE
AFTER
In terms of central tendency and variability.
citoolkit.com
Structure
A box plot is made up of a box and two whiskers.
Box Plot 11
Box Whisker
Whisker
Interquartile Range
The maximum length of a whisker is limited to 1.5 times the interquartile range (IQR).
citoolkit.com
Structure
Box plots summarize key statistics from the data.
Box Plot 12
Median Maximum value
Minimum value
●
●
Lower quartile Upper quartile
The middle line is the median of the data points.
citoolkit.com
Structure
The data is plotted such as . . .
The middle 50% of the data points
The top 25% of the data
points
The bottom 25% of the
data points
25% 25%
Quartile Group 4
Quartile Group 1
Interquartile Range
Note: When the median line is not present in the box plot, it suggests that it coincides
with one of the quartiles.
Box Plot 13
citoolkit.com
Structure
Sometimes the mean is displayed with a special character.
Box Plot 14
Median
Mean
Other character can indicate the mean such as a diamond or a plus.
citoolkit.com
Structure
Any data beyond the whiskers are considered outliers.
Box Plot 15
*
Outlier values
If the values are real, you should
investigate what was going on in
the process at that time.
Outliers often reflect errors in data
recording or data entry
citoolkit.com
Structure
Box Plot 16
*
Outlier
Median
Mean
25% 25%
Quartile Group 4
Quartile Group 1
Interquartile Range
25%
25%
Maximum value
Minimum value Lower quartile Upper quartile
Box
Whisker
●
citoolkit.com
Data Size
Like histograms, used for moderate to large amount of data.
Box Plot 17
N = 40 N = 14
The size of the box plot can vary significantly if the data size is too small.
citoolkit.com
Individual Value Plots
Individual Value Plots are preferred over boxplots when representing small
amount of data.
Box Plot 18
citoolkit.com
Symmetric Distribution
Can tell whether the distribution is symmetrical or skewed.
Box Plot 19
Symmetric
Non symmetric
Mean Median
In a symmetric distribution, the mean and median are nearly the same, and the two
whiskers has almost the same length.
citoolkit.com
Example – Crop Yield
The following box plots display the yield of a crop resulting from the
application of two different fertilizers.
Box Plot 20
Fertilizer #2 appears to yield higher crop
yields than Fertilizer #1. What other
comments would you make about the
above box plots? Think about the
variation as well as the presence of any
unusual values or outliers.
Fertilizer 2
Fertilizer 1
55
50
45
40
35
Yield
Data source: Minitab
What other comments would you make
about the above boxplots?
Think about the variation as well as the
presence of any unusual values.
citoolkit.com
Example – Diabetes Test
The below box plots illustrate an analysis that was conducted for diagnosing
the presence of diabetes at a workplace.
Box Plot 21
Female Male
500
400
300
200
100
0
Gender
Test
results
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
It is evident that females have in general
higher glucose levels than males.
To confirm the statistical significance of
this difference, ANOVA can be applied to
compare the means between the two
groups.
citoolkit.com
Further Information
There are many applications and online services that allow the creation of
box plots quickly and easily (such as Minitab, JMP, and SPSS).
Box Plot 22
© Copyright Citoolkit.com. All Rights Reserved.
CITOOLKIT
Made with by
The Continuous Improvement Toolkit
www.citoolkit.com

More Related Content

Similar to The Role of Box Plots in Comparing Multiple Data Sets

TSTD 6251  Fall 2014SPSS Exercise and Assignment 120 PointsI.docx
TSTD 6251  Fall 2014SPSS Exercise and Assignment 120 PointsI.docxTSTD 6251  Fall 2014SPSS Exercise and Assignment 120 PointsI.docx
TSTD 6251  Fall 2014SPSS Exercise and Assignment 120 PointsI.docx
nanamonkton
 
Chap004.ppt
Chap004.pptChap004.ppt
Chap004.ppt
najwalyaa
 
5Association AnalysisBasic Concepts an.docx
 5Association AnalysisBasic Concepts an.docx 5Association AnalysisBasic Concepts an.docx
5Association AnalysisBasic Concepts an.docx
ShiraPrater50
 
Data visualization
Data visualizationData visualization
Data visualization
Tony Nguyen
 
Data visualization
Data visualizationData visualization
Data visualization
James Wong
 

Similar to The Role of Box Plots in Comparing Multiple Data Sets (20)

XL-MINER: Associations
XL-MINER: AssociationsXL-MINER: Associations
XL-MINER: Associations
 
Chap004.ppt
Chap004.pptChap004.ppt
Chap004.ppt
 
TSTD 6251  Fall 2014SPSS Exercise and Assignment 120 PointsI.docx
TSTD 6251  Fall 2014SPSS Exercise and Assignment 120 PointsI.docxTSTD 6251  Fall 2014SPSS Exercise and Assignment 120 PointsI.docx
TSTD 6251  Fall 2014SPSS Exercise and Assignment 120 PointsI.docx
 
box plot or whisker plot
box plot or whisker plotbox plot or whisker plot
box plot or whisker plot
 
Chap004.ppt
Chap004.pptChap004.ppt
Chap004.ppt
 
lecture 2 Slides.pptx
lecture 2 Slides.pptxlecture 2 Slides.pptx
lecture 2 Slides.pptx
 
Effective Data Viewing in Sale Trend Analysis by using Data Cube
Effective Data Viewing in Sale Trend Analysis by using Data CubeEffective Data Viewing in Sale Trend Analysis by using Data Cube
Effective Data Viewing in Sale Trend Analysis by using Data Cube
 
Bba 2001
Bba 2001Bba 2001
Bba 2001
 
1.1 data analytics case studies and examples
1.1 data analytics case studies and examples1.1 data analytics case studies and examples
1.1 data analytics case studies and examples
 
Tableau - box plot
Tableau - box plotTableau - box plot
Tableau - box plot
 
5Association AnalysisBasic Concepts an.docx
 5Association AnalysisBasic Concepts an.docx 5Association AnalysisBasic Concepts an.docx
5Association AnalysisBasic Concepts an.docx
 
03 chapter 3 application .pptx
03 chapter 3 application .pptx03 chapter 3 application .pptx
03 chapter 3 application .pptx
 
Python for Data Science
Python for Data SciencePython for Data Science
Python for Data Science
 
Basic Statistics to start Analytics
Basic Statistics to start AnalyticsBasic Statistics to start Analytics
Basic Statistics to start Analytics
 
Data visualization
Data visualizationData visualization
Data visualization
 
Data visualization
Data visualizationData visualization
Data visualization
 
Data visualization
Data visualizationData visualization
Data visualization
 
Data visualization
Data visualizationData visualization
Data visualization
 
Data visualization
Data visualizationData visualization
Data visualization
 
Data visualization
Data visualizationData visualization
Data visualization
 

More from CIToolkit

More from CIToolkit (20)

Continuous Improvement Infographics for Learning
Continuous Improvement Infographics for LearningContinuous Improvement Infographics for Learning
Continuous Improvement Infographics for Learning
 
Continuous Improvement Posters for Learning
Continuous Improvement Posters for LearningContinuous Improvement Posters for Learning
Continuous Improvement Posters for Learning
 
Simplifying Complexity: How the Four-Field Matrix Reshapes Thinking
Simplifying Complexity: How the Four-Field Matrix Reshapes ThinkingSimplifying Complexity: How the Four-Field Matrix Reshapes Thinking
Simplifying Complexity: How the Four-Field Matrix Reshapes Thinking
 
Unlocking Productivity and Personal Growth through the Importance-Urgency Matrix
Unlocking Productivity and Personal Growth through the Importance-Urgency MatrixUnlocking Productivity and Personal Growth through the Importance-Urgency Matrix
Unlocking Productivity and Personal Growth through the Importance-Urgency Matrix
 
Measuring True Process Yield using Robust Yield Metrics
Measuring True Process Yield using Robust Yield MetricsMeasuring True Process Yield using Robust Yield Metrics
Measuring True Process Yield using Robust Yield Metrics
 
Beyond the Five Whys: Exploring the Hierarchical Causes with the Why-Why Diagram
Beyond the Five Whys: Exploring the Hierarchical Causes with the Why-Why DiagramBeyond the Five Whys: Exploring the Hierarchical Causes with the Why-Why Diagram
Beyond the Five Whys: Exploring the Hierarchical Causes with the Why-Why Diagram
 
How-How Diagram: A Practical Approach to Problem Resolution
How-How Diagram: A Practical Approach to Problem ResolutionHow-How Diagram: A Practical Approach to Problem Resolution
How-How Diagram: A Practical Approach to Problem Resolution
 
From Goals to Actions: Uncovering the Key Components of Improvement Roadmaps
From Goals to Actions: Uncovering the Key Components of Improvement RoadmapsFrom Goals to Actions: Uncovering the Key Components of Improvement Roadmaps
From Goals to Actions: Uncovering the Key Components of Improvement Roadmaps
 
Paired Comparison Analysis: A Practical Tool for Evaluating Options and Prior...
Paired Comparison Analysis: A Practical Tool for Evaluating Options and Prior...Paired Comparison Analysis: A Practical Tool for Evaluating Options and Prior...
Paired Comparison Analysis: A Practical Tool for Evaluating Options and Prior...
 
The Final Activity in Project Management
The Final Activity in Project ManagementThe Final Activity in Project Management
The Final Activity in Project Management
 
From Red to Green: Enhancing Decision-Making with Traffic Light Assessment
From Red to Green: Enhancing Decision-Making with Traffic Light AssessmentFrom Red to Green: Enhancing Decision-Making with Traffic Light Assessment
From Red to Green: Enhancing Decision-Making with Traffic Light Assessment
 
Mind Mapping: A Visual Approach to Organize Ideas and Thoughts
Mind Mapping: A Visual Approach to Organize Ideas and ThoughtsMind Mapping: A Visual Approach to Organize Ideas and Thoughts
Mind Mapping: A Visual Approach to Organize Ideas and Thoughts
 
Adapting to Change: Using PEST Analysis for Better Decision-Making
Adapting to Change: Using PEST Analysis for Better Decision-MakingAdapting to Change: Using PEST Analysis for Better Decision-Making
Adapting to Change: Using PEST Analysis for Better Decision-Making
 
Leveraging Gap Analysis for Continuous Improvement
Leveraging Gap Analysis for Continuous ImprovementLeveraging Gap Analysis for Continuous Improvement
Leveraging Gap Analysis for Continuous Improvement
 
Flowcharting: The Three Common Types of Flowcharts
Flowcharting: The Three Common Types of FlowchartsFlowcharting: The Three Common Types of Flowcharts
Flowcharting: The Three Common Types of Flowcharts
 
Yokoten: Enhancing Performance through Best Practice Sharing
Yokoten: Enhancing Performance through Best Practice SharingYokoten: Enhancing Performance through Best Practice Sharing
Yokoten: Enhancing Performance through Best Practice Sharing
 
Value Analysis: How Lean Thinking Defines Value
Value Analysis: How Lean Thinking Defines ValueValue Analysis: How Lean Thinking Defines Value
Value Analysis: How Lean Thinking Defines Value
 
The Main Components of an Effective Visual Management System
The Main Components of an Effective Visual Management SystemThe Main Components of an Effective Visual Management System
The Main Components of an Effective Visual Management System
 
Process Charts and Process Sequence Charts: Tools for Process Improvement
Process Charts and Process Sequence Charts: Tools for Process ImprovementProcess Charts and Process Sequence Charts: Tools for Process Improvement
Process Charts and Process Sequence Charts: Tools for Process Improvement
 
Achieving Business and Personal Goals with SWOT Analysis
Achieving Business and Personal Goals with SWOT AnalysisAchieving Business and Personal Goals with SWOT Analysis
Achieving Business and Personal Goals with SWOT Analysis
 

Recently uploaded

LECTURE maintenance management is important 1.pptx
LECTURE maintenance management is important 1.pptxLECTURE maintenance management is important 1.pptx
LECTURE maintenance management is important 1.pptx
shahzadnasim3
 
Disaster management for class 10 students
Disaster management for class 10 studentsDisaster management for class 10 students
Disaster management for class 10 students
madhav072009
 

Recently uploaded (13)

Marketing Management 16 Global Edition by Philip Kotler test bank.docx
Marketing Management 16 Global Edition by Philip Kotler test bank.docxMarketing Management 16 Global Edition by Philip Kotler test bank.docx
Marketing Management 16 Global Edition by Philip Kotler test bank.docx
 
Spring-2024-Priesthoods of Augustus Yale Historical Review
Spring-2024-Priesthoods of Augustus Yale Historical ReviewSpring-2024-Priesthoods of Augustus Yale Historical Review
Spring-2024-Priesthoods of Augustus Yale Historical Review
 
DrupalCamp Atlanta 2022 - Effective Project Management
DrupalCamp Atlanta 2022 - Effective Project ManagementDrupalCamp Atlanta 2022 - Effective Project Management
DrupalCamp Atlanta 2022 - Effective Project Management
 
W.H.Bender Quote 62 - Always strive to be a Hospitality Service professional
W.H.Bender Quote 62 - Always strive to be a Hospitality Service professionalW.H.Bender Quote 62 - Always strive to be a Hospitality Service professional
W.H.Bender Quote 62 - Always strive to be a Hospitality Service professional
 
Group work -meaning and definitions- Characteristics and Importance
Group work -meaning and definitions- Characteristics and ImportanceGroup work -meaning and definitions- Characteristics and Importance
Group work -meaning and definitions- Characteristics and Importance
 
LECTURE maintenance management is important 1.pptx
LECTURE maintenance management is important 1.pptxLECTURE maintenance management is important 1.pptx
LECTURE maintenance management is important 1.pptx
 
thesis-and-viva-voce preparation for research scholars
thesis-and-viva-voce preparation for research scholarsthesis-and-viva-voce preparation for research scholars
thesis-and-viva-voce preparation for research scholars
 
Using KPI's to measure Organizational Performance IPA 2023.pdf
Using KPI's to measure Organizational Performance IPA 2023.pdfUsing KPI's to measure Organizational Performance IPA 2023.pdf
Using KPI's to measure Organizational Performance IPA 2023.pdf
 
What Motivates You Assessment- Analysing Motivation
What Motivates You Assessment- Analysing MotivationWhat Motivates You Assessment- Analysing Motivation
What Motivates You Assessment- Analysing Motivation
 
Internal Reconstruction Corporate accounting by bhumika Garg
Internal Reconstruction Corporate accounting by bhumika GargInternal Reconstruction Corporate accounting by bhumika Garg
Internal Reconstruction Corporate accounting by bhumika Garg
 
Persuasive and Communication is the art of negotiation.
Persuasive and Communication is the art of negotiation.Persuasive and Communication is the art of negotiation.
Persuasive and Communication is the art of negotiation.
 
W.H.Bender Quote 63 You Must Plan T.O.P Take-Out Packaging
W.H.Bender Quote 63 You Must Plan T.O.P Take-Out PackagingW.H.Bender Quote 63 You Must Plan T.O.P Take-Out Packaging
W.H.Bender Quote 63 You Must Plan T.O.P Take-Out Packaging
 
Disaster management for class 10 students
Disaster management for class 10 studentsDisaster management for class 10 students
Disaster management for class 10 students
 

The Role of Box Plots in Comparing Multiple Data Sets

  • 1. CITOOLKIT Box Plot The Role of Box Plots in Comparing Multiple Data Sets
  • 2. citoolkit.com Definition One of the best ways to analyze any process is to plot the data on a graph or chart. Box Plot 2 * X X X X X X X X X X X
  • 3. citoolkit.com Definition A box plot is a graph that shows the frequency of numeric data values. Box Plot 3 Also referred to as a Box-and- Whisker Plot as it displays the data in a box-and-whiskers format.
  • 4. citoolkit.com Applications Mainly used to explore data as well as to present the data in an easy and understandable manner. Box Plot 4 Box plots are widely used in statistics, process improvement, scientific research, economics, and in social and human sciences
  • 5. citoolkit.com Vertical vs. Horizontal Box plots can be drawn either vertically or horizontally. Box Plot 5 The length of the box plot indicates the spread of the data.
  • 6. citoolkit.com Characteristics They provide a quick way for examining the central tendency and variation present in the data. Box Plot 6 * * Outliers are usually plotted as asterisks A wider range boxplot indicates more variability.
  • 7. citoolkit.com Characteristics Box plots are useful when comparing between several data sets. Box Plot 7 A B C D In terms of central tendency and variability.
  • 8. citoolkit.com Characteristics The same continuous data can be presented graphically using histograms and box plots. Box Plot 8 Mean * ●
  • 9. citoolkit.com Characteristics Less detailed than histograms and take up less space which make them more practical when comparing multiple data sets. Box Plot 9
  • 10. citoolkit.com Uses Used to check if there is a significant difference in the process after implementing process improvement. Box Plot 10 BEFORE AFTER In terms of central tendency and variability.
  • 11. citoolkit.com Structure A box plot is made up of a box and two whiskers. Box Plot 11 Box Whisker Whisker Interquartile Range The maximum length of a whisker is limited to 1.5 times the interquartile range (IQR).
  • 12. citoolkit.com Structure Box plots summarize key statistics from the data. Box Plot 12 Median Maximum value Minimum value ● ● Lower quartile Upper quartile The middle line is the median of the data points.
  • 13. citoolkit.com Structure The data is plotted such as . . . The middle 50% of the data points The top 25% of the data points The bottom 25% of the data points 25% 25% Quartile Group 4 Quartile Group 1 Interquartile Range Note: When the median line is not present in the box plot, it suggests that it coincides with one of the quartiles. Box Plot 13
  • 14. citoolkit.com Structure Sometimes the mean is displayed with a special character. Box Plot 14 Median Mean Other character can indicate the mean such as a diamond or a plus.
  • 15. citoolkit.com Structure Any data beyond the whiskers are considered outliers. Box Plot 15 * Outlier values If the values are real, you should investigate what was going on in the process at that time. Outliers often reflect errors in data recording or data entry
  • 16. citoolkit.com Structure Box Plot 16 * Outlier Median Mean 25% 25% Quartile Group 4 Quartile Group 1 Interquartile Range 25% 25% Maximum value Minimum value Lower quartile Upper quartile Box Whisker ●
  • 17. citoolkit.com Data Size Like histograms, used for moderate to large amount of data. Box Plot 17 N = 40 N = 14 The size of the box plot can vary significantly if the data size is too small.
  • 18. citoolkit.com Individual Value Plots Individual Value Plots are preferred over boxplots when representing small amount of data. Box Plot 18
  • 19. citoolkit.com Symmetric Distribution Can tell whether the distribution is symmetrical or skewed. Box Plot 19 Symmetric Non symmetric Mean Median In a symmetric distribution, the mean and median are nearly the same, and the two whiskers has almost the same length.
  • 20. citoolkit.com Example – Crop Yield The following box plots display the yield of a crop resulting from the application of two different fertilizers. Box Plot 20 Fertilizer #2 appears to yield higher crop yields than Fertilizer #1. What other comments would you make about the above box plots? Think about the variation as well as the presence of any unusual values or outliers. Fertilizer 2 Fertilizer 1 55 50 45 40 35 Yield Data source: Minitab What other comments would you make about the above boxplots? Think about the variation as well as the presence of any unusual values.
  • 21. citoolkit.com Example – Diabetes Test The below box plots illustrate an analysis that was conducted for diagnosing the presence of diabetes at a workplace. Box Plot 21 Female Male 500 400 300 200 100 0 Gender Test results * * * * * * * * * * * * * * * * It is evident that females have in general higher glucose levels than males. To confirm the statistical significance of this difference, ANOVA can be applied to compare the means between the two groups.
  • 22. citoolkit.com Further Information There are many applications and online services that allow the creation of box plots quickly and easily (such as Minitab, JMP, and SPSS). Box Plot 22
  • 23. © Copyright Citoolkit.com. All Rights Reserved. CITOOLKIT Made with by The Continuous Improvement Toolkit www.citoolkit.com