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BUS304 – Data Presentation 1
Graphs
Visual presentation of data
Pie Chart
Bar Chart
Line Chart
Scatter Chart
BUS304 – Data Presentation 2
A good graph should
Accurately conveys the information
Grabs the reader’s attention (visually enjoyable)
Complements or demonstrates arguments presented in the text
Is simple and uncluttered
Clearly shows trends or differences in the data
Is visually accurate (i.e. one chart value is 15 and another is 30,
then 30 should be twice the size of 15)
BUS304 – Data Presentation 3
Why use graphs?
Graphs
Are quick and direct
Highlight the most important facts
Facilitate understanding of the data
Can convince readers
Can be easily remembered.Most of the time, creating graphs is more of an art. Both visually correct data can create different
Most of the time, creating graphs is more of an art. Both visually correct data can create different
BUS304 – Data Presentation 4
Not always good to use graphs
The data are very dispersed The data are very numerous
BUS304 – Data Presentation 5
Not always good to use graphs
There are too few data The data show little variations
Sometimes, you may need to try different graphs, and may determine not to use graph in the end.
Sometimes, you may need to try different graphs, and may determine not to use graph in the end.
BUS304 – Data Presentation 6
Usually present categorical and numerical variables grouped in class or intervals
Can be either horizontal of vertical
Bar chart
0
10
20
30
40
50
60
1993 1994 1995 1996 1997 1998
0 10 20 30 40 50 60
1993
1994
1995
1996
1997
1998
Title
0
10
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60
1993 1994 1995 1996 1997 1998
X Axis
Y A
xis
Legend
category names
values
BUS304 – Data Presentation 7
Create a basic bar chart Open file “data2.xls” Create a bar chart using the data in sheet 1
Note that in Excel, the vertical bar chart is called “Column” Think: do you prefer vertical bars or horizontal bars?
BUS304 – Data Presentation 8
Other Bar Charts
Side by side bars / stacked bars / 100% stacked bars when more than one piece of info in one category
Create these three charts using data from sheet 1. Compare the difference of the key information each chart conveys
Legend is important in those charts
Legend is important in those charts
BUS304 – Data Presentation 9
Pie Chart A way of summarizing a set of categorical data Convenient to present the proportion of each category It is generally more difficult to convey the actual amount
Works especially when there are not too many categories and the proportions are significantly different from categories.
BUS304 – Data Presentation 10
ExerciseUse the data in sheet 2 to create a Pie chart.
Compare it with the bar chart. Discuss the different information it conveys
BUS304 – Data Presentation 11
Line Chart
Especially useful in statistics and science. To reflect the trend.
Can draw multiple lines in one graph for comparison.
0
200
400
600
800
1000
1200
1400
1600
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2000
1996 1997 1998 1999 2000 2001 2002
No. of Men
No. of Women
Note: when using Excel to generate a line chart, the X-axis is stillregarded as categorical names.It does not have numerical value
Note: when using Excel to generate a line chart, the X-axis is stillregarded as categorical names.It does not have numerical value
Exercise: Sheet 1
BUS304 – Data Presentation 12
Scatter Chart Mostly used in science and statistics to reflect the
sample location. X-axis and y-axis both have numerical values Shows data correlations (positive, negative, etc.)
BUS304 – Data Presentation 13
Observe data correlation from scatter chart
Find the data from sheet 3.
Draw scatter chart using
Sq. Feet as x-axis, Price as y-axis
Age as x-axis, Price as y-axis
No. of bedrooms as x-axis, Price as y-axis
No. of bathrooms as x-axis, Price as y-axis
No. of garages as x-axis, Price as y-axis
BUS304 – Data Presentation 14
Summary
4 Basic types of charts:
Bar chart
Pie chart
Line chart
Scatter chart
Know how to create a
chart from Excel
Know how to read the
chart (find a value given
a certain condition)
Know the characteristics,
and be able to pick the
best chart to convey info.