1. Graphing & Statistics
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2. Importance Provide a lot of information in a small amount of space.
Represent information at a glance
Replace the need for lots of words in a given context
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3. Graphs vs. Charts Graphs are used to show trends in data
Tables are used to show exact values of the data
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4. Types of Graphs
1) Pictograph- A graph used to compare data using symbols or graphics.
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5. Types of Graphs
2) Pie Chart- A graph used to compare parts of a whole.
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6. Types of Graphs
Bar graph – A graph using parallel bars or rectangles to compare information
When you can break your data into distinct groups
Non-continuous data
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7. Types of Graphs
Line graph- A graph comparing two variables that are plotted on a horizontal and vertical axis.
Usually used with continuous data, i.e. time
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8. Line Graphs The horizontal axis is called the “x-axis”
The vertical axis is called the “y-axis”
Y-axis
X-axis
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9. Creating a Line Graph Title your graph – Be specific!
Place the name of the independent variable (what you’re testing) on the x-axis. Include your units!
Place the name of the dependent variable (what you’re measuring) on the y-axis. Include your units!
Name of Graph
Dependent Variable
Independent Variable
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10. Use Appropriate Scale
Using real graph paper, draw your scale (distances between grid spaces) on your axes.
Make them big enough so that you can see your data comfortably.
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11. More on Scale Your scale should cover the ranges of your data set.
It does not have to start at 0
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12. Draw A Best Fit Line
Graph all of the points for your dataset or table.
Draw a “best fit” line (linear regression) between them.
Drawn as an average between all the points shown.
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13. Add A Figure Caption
Figure captions (placed below the figure) contain the details of what the figure represents.
For instance, a caption for the tree growth data might tell how many replicates were done, that the trees measured were from a open field, how long the trees grew for, etc.
Tables have titles (placed above the Table). A title is a relatively brief description of the table.
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14. Statistical Analysis on data sets
Mean - the average value of your data set.
Example: 2,4,3,2,4,3
What is the average?
2. Median - the middle value in your data set
Arrange data in increasing (or decreasing) order.
Odd number of data points = use value in middle
Even number of data points = use the value half-way between the
two center points.
Example: 3,8,4,1,7,4,3,9,6,4,8
3. Mode (fashion) - the most common value in your data set
Can have more than one
Not always representative of the data
4. Range - the difference between the largest number and the smallest number in the group.
Example: 1,3,8,6,8
8 is the largest and 1 the smallest number
Hence range is 8-1 = 7
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