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Graphing Exercise 1. Create a Pie Graph by Selecting a Data Table
This exercise selects the data in an existing data table and creates a pie graph of the data (Figure G1).
Figure G1. Tree species sampled in schoolyard phenology study at Athol- Royalston Middle School, 2004-2007.
Educational Goals of Exercise
Become comfortable with working within a spreadsheet to:
- Select data you want to graph
- Choose a graph type for your data
- Create a graph
- Format the graph
- Consider the mathematics involved in creating a pie chart
Summary of Steps*
- Input a new data table of tree-species data into your worksheet (Table G1).
- Select both columns of Tree Species data in the table you created.
- Instruct the computer to insert a pie graph.
- Format and edit the completed graph as you choose.^1
- If you are using a program other than Excel, the steps may differ somewhat from those presented here.
Table G1. Breakdown of sampled trees by species, ARM Schoolyard Phenology Study, 2004-2007.
Tree Species Beech
Number of Trees 2 Chestnut 2 Hawthorn 1 Red maple 4 Witch Hazel 1 Yellow Birch 1
(^1) NOTE: Formatting and editing a pie chart can include specifying a title,
adjusting the legend, changing colors for individual pieces of the pie, deciding whether to include data values on the graph and where to put them, choosing whether to have a solid pie or one with the pieces exploded, and various other options. Take the time to explore ways to change the appearance of the pie chart you have created, and consider how the changes enhance or fail to enhance the story you want to tell.
Educational Goals of Exercise
Practice, and become comfortable with, specifying data to be graphed using Data Source dialog boxes in Excel, or comparable graph-creation methods in other graphing programs.
Summary of Steps*
- Click on a blank cell in your worksheet.
- Tell the computer to insert a graph, and select the type of graph you want to create.
- Use the Data Source dialog box to select a data range for graphing from a data table.
- Use the Data Source dialog box to specify individual data to be graphed, creating a series.
- Format/edit the graph, as appropriate – format axis titles, change font size, adjust the range, alter fonts and colors, and make other changes to make your graph attractive and informative.
- Take a few minutes to consider how different formatting options enhance or otherwise contribute to (or detract from) the message conveyed by the graph, Also, compare the graph you just made with the pie chart made in Exercise 1. Does one do a better job, in your opinion, of showing the information you want a viewer to see?
- If you are using a program other than Excel, the steps may differ somewhat from those presented here.
Graphing Exercise 3. Creating a Simple Bar Graph from an Existing Graph
Most graphing programs allow you to convert one kind of graph into another kind without having to go through all the steps involved in creating the graph from a data table. In this exercise, you will use the Chart Type dialog box in Excel, or the comparable tools in other graphing programs, to convert an existing graph into another kind of graph, specifically the simple bar graphs shown in Figure G3.
Figure G3. Two versions of simple bar graphs produced from the pie graph and stacked bar graph in Figures G1 and G2.
Left, graph produced by specifying that data are in rows.
Right, graph produced by specifying that data are in columns.
Educational Goals of Exercise
Develop facility with tools provided by your graphing program to change an existing graph into another kind of graph.
- In Excel, become familiar with commands such as Switch Rows/Columns command, the Change Chart Type dialog, and the Source Data dialog boxes
- In other graphing programs, practice using the comparable tools.
Graphing Exercise 4. Graph Leaf-Fall Data from One Tree
This exercise will graph leaf fall from a single tree over four years of sampling. The graph will be similar to Figure G4.
Figure G4. Progression of leaf fall in a yellow birch sampled in 2004-2007 by students at Athol-Royalston Middle School
Educational Objectives of Exercise
Build on what you learned in the earlier exercises to create a complex graph
from multiple years of data.
• Review and practice sorting data in an Excel spreadsheet
• Learn how to convert count data in a spreadsheet to percentages
• Become comfortable with using the Source Data dialog to create a
complex graph.
• Increase confidence in formatting the graph to produce a clear
presentation of the results
• Further develop skills in interpreting the message the graph provides
Sampling date
Percent of Leaves Fallen
Summary of Steps*
1. Download fall data from Athol-Royalston Middle School (ARM).
2. Sort the data to organize the data by tree, so each tree’s data are presented
chronologically, together.
3. Add a new column to the data table, and in this column insert the percent
of leaves fallen for each tree on each date. (The data set shows number of
leaves fallen, so you will need to convert the number fallen on each date
into a percent of all leaves observed on that date.)
4. Insert a new graph that will show percent of leaves fallen vs. date.
Specify that you want a scatter plot with lines connecting the points.
5. Use the Source Data dialog boxes in Excel, or the comparable tool in a
different graphing program, to add the leaf-fall data for Yellow Birch
Tree YB1 from 2004, 2005, 2006, and 2007 (you may add data from later
years, if you wish).
6. Edit the graph, as appropriate. You may want to adjust the symbols used
for the different years, their colors, and their sizes; edit the legend; format
the axes to make them more readable; or make other changes to make the
graph more effective at showing the results of the study.
7. Spend a few minutes looking at the graph and thinking about the story it
tells and questions that it generates.
- If you are using a program other than Excel, the steps may differ somewhat from those presented here.
Summary of Steps*
- Create a new Data Table showing dates of first and last leaf fall
- Select the data table, including column headings
- Insert a graph, and format as necessary.
- If you are using a program other than Excel, the steps may differ somewhat from those presented here.
Table G5. Data Table for first and last leaf-fall dates for tree YB1, 2004-
Year First leaf fall
Fallen 2004 309 309 2005 271 314 2006 263 312 2007 255 304
Optional Variation: Graph the Data as a Bar Graph.
In Figure G5-2, the data in Figure G5-1 are graphed as a bar or column graph comparing matched pairs of data. As with the initial scatter chart that simply presented the data as points, it is easy to see how the dates when the students observed the first fallen leaves became earlier each year over the four years for which data are available. The similar but less consistent trend in the date of last leaf fall is also visible.
You can either create a bar graph from scratch, using the same process you used to make your scatter plot, or you can use the graphing program’s option for change an existing graph into another kind of graph.
Figure G5-2. First and last dates of leaf fall in Yellow Birch #1, 2004-2007.
When you have completed your graphs, once again, take a few minutes to look at them carefully. Is there further formatting that would make them more informative? Think about the “story” the graphs tell, and identify questions that are raised by the graphs. Are there some anomalies that might need to be explained? Some questions that suggest additional research that is needed?
Date of leaf fall (Julian day)
