© keith vander linden, 2005 1 graphs and charts ● quantitative data can frequently be illustrated...
TRANSCRIPT
© Keith Vander Linden, 2005
1
Graphs and Charts
● Quantitative data can frequently be illustrated in a compelling way using charts and graphs.– see www.gapminder.org for fascinating,
interactive charts
● Spreadsheet systems usually provide graphing and charting capabilities.
● Here are some examples.
© Keith Vander Linden, 2005
© Keith Vander Linden, 2005
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Bar chart of same data
© Keith Vander Linden, 2005
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Pie chart of same data
© Keith Vander Linden, 2005
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image from VDQI, 1983
© Keith Vander Linden, 2005
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Chart Types● Pie charts
– proportional relationships
● Column/bar charts– relative numeric information– (rather than percentages)
● Line charts– change in values over time
● Maps– geographical information– spatial relationships
Financial A id; $20.8
Food; $6.0
B enefits;
$15.6 S alaries;
$35.3
Other; $23.5
Calvin Expenditures, 2003-2004
Bush Kerry Nader Badnarik Cobb Peroutka Brown
0%
10%
20%
30%
40%
50%
60%
48%51%
1% 0% 0% 0% 0%
2004 Election Voting Percentages - Michigan
Candidate
Pe
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ge
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
3,7003,8003,9004,0004,1004,2004,3004,400
College Enrollments
Year
En
roll
men
t
© Keith Vander Linden, 2005
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Graph/Chart Issues
● Data values can, however, be obscured or misrepresented using charts.
● Here are some examples.
© Keith Vander Linden, 2005
© Keith Vander Linden, 2005
© Keith Vander Linden, 2005
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image from VDQI, 1983
© Keith Vander Linden, 2005
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image from VDQI, 1983
© Keith Vander Linden, 2005
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image from VDQI, 1983
© Keith Vander Linden, 2005
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Lying graphics cheapen the graphical art everywhere … When a chart on television lies, it lies millions of times over; when a New York Times chart lies, it lies 900,000 times over to a great many important and influential readers. VDQI, p. 53-79
Edward Tufte (1940-) VDQI, 1983
images from www.edwardtufte.com, Oct., 2004
© Keith Vander Linden, 2005
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from Calvin College Chimes, Oct. 6, 2000
© Keith Vander Linden, 2005
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image from Exploring Microsoft Excel 97, Grauer & Barber, 1998
Calvin20%
Hope25%
Kalamazoo30%
Wheaton25%
© Keith Vander Linden, 2005
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image from Exploring Microsoft Excel 97, Grauer & Barber, 1998
2002 2003 2004 2005$0
$10
$20
$30
$40
$50
MyCompany.com
profit
sales
Year
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© Keith Vander Linden, 2005
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Using Charts/Graphs Properly
● Decide what you want to present.● Present it accurately and unambiguously.
– Let the graphic values/change accurately depict the data values/change.
– Clearly label all relevant details.– Don’t graphically mix dissimilar elements.– Use the right type of graph.– Don’t add “chartjunk”.
© Keith Vander Linden, 2005
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Technology and Lying● It is as easy to lie or mislead with
technology.
● “When he lies, he speaks his native language, for he is a liar and the father of lies.” - John 8:44
What’s theBig Idea