Data Presentation

1
Data Presentation

• Using Descriptive Graphs

Introduction to Business Statistics, 5e
Kvanli/Guynes/Pavur (c)2000 South-Western
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2
Constructing a Frequency Distribution

• 1. Gather the data.
• 2. Arrange the data in an ordered array.
• 3. Select the number of classes.
• 4. Determine the class width.
• 5. Determine the class limits for each class.
• 6. Count the number of data items in each class.
• 7. Summarize into a frequency distribution table.

Introduction to Business Statistics, 5e
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3
Frequency Distribution

• Number of Classes (K) value chosen to best
  represent the data
• Class Width (CW)

Introduction to Business Statistics, 5e
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4
Frequency Distribution for Continuous Data
Introduction to Business Statistics, 5e
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5
Frequency Distribution for Continuous Data
Introduction to Business Statistics, 5e
Kvanli/Guynes/Pavur (c)2000 South-Western
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6
Frequency Distribution for Discrete Data
Introduction to Business Statistics, 5e
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7
Histogram

• A Histogram is a graphical representation of a
  frequency distribution for continuous data.
• The height is proportional to the frequency of
  that class

Introduction to Business Statistics, 5e
Kvanli/Guynes/Pavur (c)2000 South-Western
College Publishing
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Introduction to Business Statistics, 5e
Kvanli/Guynes/Pavur (c)2000 South-Western
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9
Introduction to Business Statistics, 5e
Kvanli/Guynes/Pavur (c)2000 South-Western
College Publishing
10
Stem-and-Leaf Diagrams

• Stem-and-Leaf Diagrams were developed to
  summarize data without loss of information.

Introduction to Business Statistics, 5e
Kvanli/Guynes/Pavur (c)2000 South-Western
College Publishing
11
Stem-and-Leaf DiagramsIllustration
Reports of the after-tax profits of 12 companies
are (recorded as cents per dollar of revenue)
as follows 3.4, 4.5, 2.3, 2.7, 3.8, 5.9, 3.4,
4.7, 2.4, 4.1, 3.6, 5.1
Stem Leaf (unit .1)
2 3 4 5
3 4 7 4 4 6 8 1 5 7 1 9
Introduction to Business Statistics, 5e
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12
Stem-and-Leaf
By rotating the Stem-and-Leaf we get an image
of the shape of the data.
3 4 7 4 4 6 8 1 5 7 1 9
Stem Leaf (unit .1)
2 3 4 5
Introduction to Business Statistics, 5e
Kvanli/Guynes/Pavur (c)2000 South-Western
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13
Figure 2.9
Introduction to Business Statistics, 5e
Kvanli/Guynes/Pavur (c)2000 South-Western
College Publishing
14
Frequency Polygon

• A frequency polygon is a graph that represents
  the shape of the data. It can be conceptualized
  as a connection of the midpoints of the classes
  at the height specified by the frequency.

Introduction to Business Statistics, 5e
Kvanli/Guynes/Pavur (c)2000 South-Western
College Publishing
15
Relative Frequency Polygon

• A relative frequency polygon is similar to a
  frequency polygon, except that the height is
  dictated by the relative frequency

Introduction to Business Statistics, 5e
Kvanli/Guynes/Pavur (c)2000 South-Western
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Figure 2.17
Introduction to Business Statistics, 5e
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Cumulative Frequencies

• A Cumulative Frequency table provides
  information on the number of values that are less
  than the upper class limit.

Introduction to Business Statistics, 5e
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Introduction to Business Statistics, 5e
Kvanli/Guynes/Pavur (c)2000 South-Western
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19
Bar Charts

• Bar Charts are used for graphical representation
  of Nominal and Ordinal data.
• As with a Histogram the height of the bar is
  proportional to the number of values in the
  category.

Introduction to Business Statistics, 5e
Kvanli/Guynes/Pavur (c)2000 South-Western
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20
Figure 2.20
Introduction to Business Statistics, 5e
Kvanli/Guynes/Pavur (c)2000 South-Western
College Publishing
21
Pie Chart

• The Pie Chart is an alternative to the Bar Chart
  for Nominal and Ordinal data.
• The proportion of the Pie represents the
  categorys percentage in the population or sample.

Introduction to Business Statistics, 5e
Kvanli/Guynes/Pavur (c)2000 South-Western
College Publishing
22
Figure 2.23
23
Deceptive Graphs

• If care is not taken in constructing graphs, the
  graph may not properly present the data.
• Also, Graphs can be purposely manipulated to
  provide false impressions of the data.

Introduction to Business Statistics, 5e
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Common Deceptive GraphsFigure 2.26
Introduction to Business Statistics, 5e
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Common Deceptive Graphs Figure 2.27
Introduction to Business Statistics, 5e
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Common Deceptive Graphs Figure 2.28
Introduction to Business Statistics, 5e
Kvanli/Guynes/Pavur (c)2000 South-Western
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