Transcript Graphing Using Excel

Graphing Using Excel
Part I: Creating simple graphs
University of Michigan – Dearborn
Science Learning Center
Written and Created by:
James Golen
V.3
Introduction:
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Before using this module you must already
know the basics of using Microsoft Excel, or be
fluent in a similar form of spreadsheet/data
entry software.
In addition, make sure that you understand the
basics of graphing in general. If you need help
with basic graphing, please refer to the
Introduction to Graphing module available
from the Science Learning Center.
This module has been created for the sole
purpose of providing graphing experience
using Microsoft Excel software. This module is
not a tutorial of Excel’s capabilities!
Getting Started
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You’ve collected the data from your
experiment. Now you must make a graph.
Graphing by hand is a option, but using a
computer program will make your results more
accurate and look more professional.
Begin by sorting the data into dependent and
independent variables.
Example:
Independent Dependent
1
1.5
2
3
3
5.5
4
4.4
5
6.8
6
8.8
Getting Started
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Step 1:
With your data separated, open an Excel
spreadsheet. Begin entering your data.
Enter your raw data into the
spreadsheet. Placement of
your data will depend on
how many descriptors that
you will need to label your
data. Here we use column
“C” as independent variable
(x-axis), and the “D” column
for the dependent variable
(y-axis). For a simple graph,
columns “A” vs. “B” can be
used. This would be a good
time to save your data.
Graphing
Step 2:
Highlight the data that you
wish to graph by holding
down the left click button,
drag over your numbers,
then release.
Only the area highlighted
will be graphed. So make
sure that you have selected
all the data that you want
to appear on your graph.
Graphing
Step 3:
With your data
highlighted, left click
on the “Chart Wizard”
in the toolbar.
Some versions of Excel
do not have this icon
displayed within the
toolbar. In such a case,
select “Insert” from the
main toolbar. A
dropdown box will
appear, select “Chart”.
Graphing
Step 4:
The Chart Wizard will
provide you with a
series of steps. “XY
(Scatter)” is a standard
choice and will be used
in most situations.
Unless you want to play
connect the dots,
choose the sub-option
without lines. Click
“Next”.
Graphing
Step 5:
At this point you have a
rough view of your
graph. If this is the
format you want click
“Next”.
Graphing
Step 6:
The Chart Wizard now will allow you to enter labels
for your graph. Enter a title, and label the X and Y
axes. Click “Finish” when complete.
The window also
provides a number of
tabs labeled, “Axes,
Gridlines, Legend, and
Data Labels”. In this
mini-module, we will
not be concerned with
these tabs. A
supplementary SLC
module entitled
Advanced Graphing
using Excel will explore
these options further.
Graphing
When complete, your graph should look like this, but our
graph is not quite finished.
Note:
Excel places your
graph toward the
center of the screen.
If this placement is
inconvenient, simply
left-click and drag.
Graphing
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Congratulations you have made a graph,
but you still have to draw a line or curve
to relate the data.
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Rarely in science do we “connect the
dots” in a graph. Rather, we would like
to show the trend of our data in the form
of a best fit line.
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How do we do this in Excel? Simple.
Graphing – Adding a Trendline
Step 1:
Let’s use the graph
we just made as an
example. At this
point make sure the
graph is highlighted.
We can tell the graph
is selected by the
small squares located
around its frame.
Graphing – Adding a Trendline
Step 2:
From the main toolbar,
select “Chart”. One of the
items in the “Chart”
dropdown box will be the
“Add Trendline….” Option.
Left click on this selection.
Graphing – Adding a Trendline
Step 3:
This selection will
allow you to choose the
trend that you wish to
show with your data.
In the case of our
graph, we have chosen
a simple linear
regression. If your
graph requires a
different type of
trendline, simply left
click on the box
showing the line you
require.
“Options” tab
To add the equation of our line,
choose the tab entitled “Options”
Graphing – Adding a Trendline
Step 4:
From the “Options”
tab, mark the check
box “Display
equation on chart”.
Click “OK”
when finished.
Graphing – Adding a Trendline
This is how your graph should look when complete.
Note:
Data labels
including your
equation can be
moved around or
even removed if
so desired. To
adjust your
labels, click and
drag to the new
position, or click
and press
“delete” on the
keyboard to
remove an item.
Make sure you continue to save your work!
Important
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It’s important to remember that knowing
how to graph with Excel does not make
up for poor graphing abilities or invalid
data.
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If you are having trouble understanding
how a graph is set up, please see a
Science Learning Center assistant.
Credits
Graphing Using Excel V.3
Created: 4/1/02
Last modified: 4/10/02
Written and Produced by: James Golen
For more information contact:
University of Michigan – Dearborn
Science Learning Center
www.umd.umich.edu/casl/natsci/slc
(313) 593-5512