Step-by-step guide to making a simple graph in Excel 2011 for Mac
Mariëlle Hoefnagels and Lauren Bobzin, University of Oklahoma
The following tutorial includes bare-bones instructions for using Microsoft Excel 2011 for Mac
to make two types of simple graphs: column/bar graphs and line (XY) graphs. At the end, you
can also find a note about using the logarithmic scale for the graphs you make for your Chicken
Wing Microbiology labs.
A. Column/Bar Graphs
Column or bar graphs are for data collected in an experiment in which the independent
variable (the one that goes on the X-axis) is qualitative (categorical), not quantitative
(numerical). As an example, perhaps you designed an experiment to determine which type of
food produces the most weight gain in your parakeet.
Step 1: Enter the data in the cells of an Excel spreadsheet, like this:
Step 2: Use the mouse to highlight the block of cells
containing your data, then click Charts. A bunch of
chart types will appear. Choose the type that says
“Column.”
Step 3: When you click on the chart type you want,
Excel automatically makes a draft of the chart
for you and pastes it into the worksheet, like
this:
Step 4: This is looking pretty good, but you’re not done because there aren’t any axis labels or
units, and the title is kind of lame. So the next step is to click on the “Chart Layout” tab, which
brings up the layout options of the graph. Part of it is shown at right.
Within this tab, you can select and change options such as the axis labels. You can also add a
title to the chart and format the legend. To edit an existing chart title, simple click the text box
containing text to rename it.
The graph below shows the new titles in
place.
We don’t need the legend on the right either, to remove it simply click the text box and press the
backspace button.
Step 5: I also like the idea of putting the chart on its own sheet, where it looks a little less
crowded and a little tidier. To do that, right click the chart (control+ click or command+ click)
and select Move Chart.
You get a little window that looks like this:
Give it a name you like. When you click OK, your chart will look really nice.
Of course, you can fool around all you want with the fonts, text sizes, bar colors, gridlines,
background color, and so forth, but I left it pretty basic.
B. Line (or XY) Graphs
Line (or XY) graphs are for data collected in an experiment in which the independent
variable (the one that goes on the X-axis) is quantitative (numerical). As an example,
perhaps you designed an experiment to determine how long it takes to boil various
volumes of water.
Step 1: Enter the data in the cells of an Excel spreadsheet, like
this:
Step 2: Use the mouse to highlight the block of cells containing
your data, then click Insert  Chart. A bunch of chart
types will appear. For Mac Excel 2011, the chart type
you want is listed under “other” labeled
“Straight Marked Scatter”.
I know you’re tempted by the Line graph
option, but don’t let it seduce you; choose
the X Y (Scatter) chart, the one with dots
and jagged lines (see the arrow in the
figure at right).
**Pay attention!** If you accidentally choose the Line graph, Excel will NOT consider
the relative values of the numbers on your X axis! In our example, the X-axis values are
100, 200, 500, and 1000. If you choose Line, you will get those numbers equally spaced.
If you pick Scatter, as you should, Excel will create a graph in which 1000 is ten times as
far away from 0 as 100 is. If you don’t believe me, try both graph types with the data I
have given you, and look at the difference.
Step 3: When you click on the chart type you want,
Excel automatically makes a draft of the chart
for you and pastes it into the worksheet (see
example at right).
Step 4: You’re still not done, though, because there
aren’t any axis labels or units, and the title is
lame. So the next step is to click on the “Chart
Layout” tab, which brings up the chart format
options. You can see a picture of it under step 4
of the instructions for making a column graph. To start with, click on the tab called
“AxisTitles,” where you can change the labels for the horizontal (X) axis and the vertical
(Y) axis. You can also add a chart title using the tab labeled “Chart Title” much like we
did in the column graph. Just for the heck of it, I also deleted the legend, because it
doesn’t add any information to this graph.
Step 5: The only thing left to do is to move the chart to its
own sheet so that the spacing looks more attractive and
proportionate. To do that, click Chart  Move Chart.
When the little window pops up, click on “New Sheet” and
click OK (see step 5 for the column graph instructions if
you want to see what this looks like).
Here’s what the final graph looks like (of course, you
can fool around all you want with the fonts,
text sizes, line color, gridlines, background
color, and so forth, but I left it pretty basic).
And that’s it! You’re done!
One last note …
For Chicken Wing Microbiology, the logarithmic scale will be your friend
In BIOL 1005, you sometimes have to graph data for which differences among the Y-axis values
are huge. For chicken wing microbiology, for example, your control wings might have billions of
bacteria per ml, whereas the treated ones “only” have thousands. In Excel’s default graphing
mode, the scale that accommodates the huge numbers will dwarf your puny values, and you will
hardly be able to see the smaller bars at all. What to do?
Answer: use the logarithmic scale! Each increment on the logarithmic scale represents a 10-fold
change. That is, whereas a linear scale goes 1, 2, 3, 4 …, the logarithmic scale goes 1, 10, 100,
1000, …
Using the logarithmic scale only makes sense when the differences among your data points are
very large. To use it, double click on the Y axis of your graph. A box called “Format Axis” will
appear. Click on “Scale,” and then tick the “Logarithmic Scale” box. The data won’t change, but
their presentation on the Y axis will, and it will make your graph much easier for you (and your
TA) to read.