Describing Data Visually

Statistics & Risk Management

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Call TEA Copyrights with any questions you have.

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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 2010Company 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

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Toyota

GM

VW

Hyundai

Ford

Nissan

Honda

PSA

Suzuki

Production: Does this tell us something?

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Call Center Sample (Calls) Can we apply this data to a pie chart?

• 6:00 am 120• 7:00 am 110• 8:00 am 160• 9:00 am 205• 10:00 am

170• 11:00 am

150• 12:00 am

170• 1:00 pm 200• 2:00 pm 170• 3:00 pm 152• 4:00 pm 140• 5:00 pm 130

• 6:00 pm 180• 7:00 pm 100• 8:00 pm 143• 9:00 pm 210• 10:00 pm 161• 11:00 pm 80• 12:00 am 40• 1:00 am 30• 2:00 am 40• 3:00 am 20• 4:00 am 10• 5:00 am 31

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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

Calls Each HourDoes this tell us something?

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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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6:00 AM

8:00 AM

10:00 AM

12:00 PM

2:00 PM

4:00 PM

6:00 PM

8:00 PM

10:00 PM

12:00 AM

2:00 AM

4:00 AM0

50

100

150

200

250

Calls Each HourDoes this tell us something?

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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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0 0.5 1 1.5 2 2.5 3 3.5 40

0.5

1

1.5

2

2.5

3

3.5

Years Experience

Time (Hours)Scatter Charting

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Scatter ChartingWhat 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?

Freshman Sophomore Junior Senior0

0.5

1

1.5

2

2.5

3

Time Spent Doing What?

Time Spent?

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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

Descriptive Scales

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• Nominal• Ordinal• Interval• Ratio