ED-STEEP: Education Solutions to Environmental
and Economic Problems
Constructing Bar and Line Graphs
This is a simple outline on how to construct line and bar graphs using Microsoft Excel. It also
gives the basic components of a proper graph for lab reports.
Components of a Good Graph
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X axis – the independent or treatment variable
Y axis – the dependent variable (e.g., what you measured or estimated)
Use the proper scale – if numbers are used, they should be in even increments; the scale
should allow you to cover most of the page
Clearly label axis, values, and units
Use “tick” marks for quantitative data
Bar graphs are best for qualitative response variables
Line graphs are best for quantitative variables
Clearly and concisely provide a caption at the bottom of the graph (see examples)
Use a legend to clarify variables, if necessary
Constructing a Bar Graph
1. Open the Excel spreadsheet.
2. Place the data for the independent variable vertically down column A.
3. Place the data for the dependent (response) variable vertically down column B.
Example:
Independent variable – habitats sampled for plants
Dependent variable – number of plant species found
1
2
3
4.
5.
6.
7.
8.
9.
A
Riparian
Forest
Old Field
B
10
20
34
Highlight the data cells by dragging the cursor over the cells.
Click on the Chart Wizard (or click Insert – Chart).
Double click on Column - this will bring up a picture of the bar graph.
Click Next.
Click on Titles.
Under Category (X) Axis, type in the name of the independent variable (e.g., Habitat
Type).
10. Under Category (Y) Axis, type in the name of the dependent variable (e.g., Number of
species).
11. Click on Legend.
12. Uncheck the Show Legend box.
13. Click on Next.
14. Click on Finish - the bar graph should now be imbedded in the spreadsheet.
15. Cut and paste the graph into your lab report.
Number of Species
40
35
30
25
20
15
10
5
0
Riparian
Forest
Old Field
Habitats
Figure 1. Number of plant species found in three habitats at Phillips
Environmental Farm, Latah County, Idaho, 2004.
Constructing a Line Graph
1. Open the Excel Spreadsheet.
2. Place the data for the independent variable vertically down column A.
3. Place the data for the dependent (response) variable vertically down column B.
Example: Independent variable – number of plant species
Dependent variable – number of beetle species
Number of Plant Species Number of Beetle Species
5
8
10
20
15
30
23
44
4.
5.
6.
7.
8.
9.
Highlight the data cells with numbers by dragging the cursor over the cells.
Click on the Chart Wizard (or click Insert – Chart).
Double click on XY (scatter) - this will bring up a picture of the line graph.
Click Next.
Click on Titles.
Under Category (X) Axis, type in the name of the independent variable (e.g., No. plant
species).
No. beetle species
10. Under Category (Y) Axis, type in the name of the dependent variable (e.g., No. beetle
species).
11. Click on Legend.
12. Uncheck the Show Legend box.
13. Click on Next.
14. Click on Finish - the bar graph should now be imbedded in the spreadsheet.
15. Cut and paste the graph into your lab report.
50
45
40
35
30
25
20
15
10
5
0
0
5
10
15
20
25
No. plant species
Figure 2. Relationship between number of beetle species and plant
species at four different sites, Phillips Environmental Farm, Latah
County, Idaho, 2004.