Graphing Data

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Graphing Data

• One picture is worth a 1000 words.
• Keep it simple
• Put only one or two variables per graph

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AIDS Knowledge Among College Students by Age
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Line Graphs

• Very popular
• Each line represents a group
• Each marker (i.e., small square) on the graph is
  the value of the particular group

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AIDS Knowledge Among College Students by Age
On the other hand, the redtriangles are
representingmalesNote that with line graphs
you can get a good general view,but not EXACT
numbers
Note, that the yellowboxes representfemale
scoresat various agegroups
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AIDS Knowledge Among College Students By Age
Here we are having four different values in this
line graph.You probably dont want to put more
than 4 values ona graph
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AIDS Knowledge Among College Students By Age
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AIDS Knowledge Among College Students by Age
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Histogram

• Another common way to display data
• Its similar to bar graph, excepts the values
  touch each other
• Good for comparisonslike line graph you cannot
  get EXACT scores.

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AIDS Knowledge Among College Students by Age
Here you see the scores of various age groups on
an AIDStest. For example, age group 15-19
scored highestapproximately78.
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AIDS Knowledge Among Various Groups
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Bar Graph

• One of the most popular methods
• Similar to histogram, excepts bars have spaces.
• Like histogram, can give comparisons, but not
  EXACT scores.

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AIDS Knowledge Among Various Groups
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AIDS Knowledge Among Various Groups
You can get real fancy with bar graphs by listing
two variableswith each scores. Note that for
each group, its broken intomales and females
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Funding of AIDS Research of Dollars
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Pie Charts

• Pie charts are the most popular of all graphsit
  has made USA Today a lot of money
• Pie charts are intended to show a proportion of a
  whole---the whole has to be the same thing (i.e.,
  money, population)

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Pie Chart

• One of the most populara USA Today theme
• Pie charts are for looking at parts of the
  WHOLEthe whole must be one theme (i.e.
  population, money)

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Funding of AIDS Research of Dollars
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1987 Illinois Population Male/Female Race
Comparison
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Pie Charts

• Check out the next pie chart.
• It looks good, but it has something wrong with
  itwhen you get to it you will have about 30
  seconds to determine what is wrong. After 30
  seconds the answer will appear.

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1987 Illinois Population Male/Female Race
Comparison
The whole consists of two different parts---sex
and raceOne cant do thatone can do white male,
white female, non-white maleand non-white
female, but not as it appears