Describing Data
Visually
Statistics &
Risk Management
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The Visual Advantage
Advantages:
• Easier to make comparisons.
• Easier to draw conclusions
• A picture is worth a 1000 words.
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Been Around for a While
Nicole Oresme,
14th Century Publication
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Pie Charting
Advantage:
• Great for a small number of groups
with large variances.
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Top 10 World Production 2010
Company
Sales by Units
Toyota
8,557,351
General Motors
8,476,192
Volkswagen
7,341,065
Hyundai
5,764,918
Ford
4,988,031
Nissan
3,982,162
Honda
3,643,057
PSA Peugeot Citroën
3,605,524
Suzuki
2,892,945
http://en.wikipedia.org/wiki/Automotive_industry
Copyright © Texas Education Agency, 2012. All rights reserved.
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Production: Does this tell us something?
Toyota
GM
VW
Hyundai
Ford
Nissan
Honda
PSA
Suzuki
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Call Center Sample (Calls)
Can we apply this data to a pie chart?
•
•
•
•
•
•
•
•
•
•
•
•
6:00 am
7:00 am
8:00 am
9:00 am
10:00 am
11:00 am
12:00 am
1:00 pm
2:00 pm
3:00 pm
4:00 pm
5:00 pm
120
110
160
205
170
150
170
200
170
152
140
130
•
•
•
•
•
•
•
•
•
•
•
•
6:00 pm
7:00 pm
8:00 pm
9:00 pm
10:00 pm
11:00 pm
12:00 am
1:00 am
2:00 am
3:00 am
4:00 am
5:00 am
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180
100
143
210
161
80
40
30
40
20
10
31
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Calls Each Hour
Does this tell us something?
6:00 AM
7:00 AM
8:00 AM
9:00 AM
10:00 AM
11:00 AM
12:00 PM
1:00 PM
2:00 PM
3:00 PM
4:00 PM
5:00 PM
6:00 PM
7:00 PM
8:00 PM
9:00 PM
10:00 PM
11:00 PM
12:00 AM
1:00 AM
2:00 AM
3:00 AM
4:00 AM
5:00 AM
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Histogram Charting
• Better when time is involved.
• Data is grouped and placed along
an axis representing time.
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Calls Each Hour
Does this tell us something?
250
200
150
100
50
0
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Scatter Charting
• Used to look for relationships
between two variables or potential
clustering
• Good for seeing a correlation or
cluster.
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Scatter Charting
Time (Hours)
3.5
3
2.5
2
1.5
1
0.5
0
0
1
2
3
4
Years Experience
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Scatter Charting
What do you think this means?
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Ogive Charting
• Utilizes a line to connect data.
• When used correctly it can predict
values between and beyond.
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Ogive Charting:
Can this chart really predict values between and beyond?
Time Spent Doing What?
3
2.5
2
Time Spent?
1.5
1
0.5
0
Freshman Sophomore
Junior
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Senior
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Descriptive Indices
• Indices are used to Identify Groups
in Comparison Studies.
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Example Indices
• Utility Bills
– Kilowatts vs. Months
• Sale Commissions
– Sales vs. Sales Person
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Descriptive Scales
•
•
•
•
Nominal
Ordinal
Interval
Ratio
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