Creating Graphs

Print out the Graphing Checklist as well as this document on creating graphs.  This document will show you how to create line graphs, pie charts and bar graphs.  You should also follow the checklist for creating an effective graphs.  Please note that after a graph/chart is created, you may edit the chart by clicking on it once and then clicking on "Chart" on the menu bar.  Most of the time, you may be able right click on the part of the chart you want to change and then make the change by following the various options that appear.

Creating Line Graphs using X-Y Scatter

Open the file O'HareTempApril2003.xls, which contains the average daily temperature as recorded at O'Hare International Airport for each day in April 1997. 

1. Select the data with the mouse.  Generally speaking it is best to select only the data, not headers and labels.  Excel sometimes handles the headers very nicely, but at other times it leads to confusion.  You are safer to leave them out.  (If the data you want to use is not in adjacent columns, select the first column of data, hold the control key and then select the other column of data.)

2. Click on the "Chart Wizard" button at the top of the screen: .  The icon depicts a chart, but it looks more like some books on a shelf.  You will get a menu that looks like:

Choose the type "XY (Scatter)" and choose the  "Scatter with data points connected by lines" subtype . 

3. Continue with the chart wizard by clicking on "Next >".  Step 2 of the chart wizard gives you a preview of the graph.   In this case it will be correct; however, if it is not, the problem often must be fixed by clicking on "Series" tab at the top of  message box.

4. Continue onto step 3.  Enter an appropriate title for the plot and appropriate labels for the x and y axes.  Be sure to address the four W's when creating your title.

5. Finally, continue onto step 4.  You will get a message box that looks like:

You are presented with two choices.  You can choose to place your plot as an object on your worksheet or as a new sheet of its own.  Both of these choices are useful.  Placing on your worksheet makes it easier to resize the plot and make it an appropriate size for transferal to a Word document.  Making the plot a new sheet makes the plot fill the screen which is useful for studying the plot and for making presentations.  Today, place the chart as an object in Sheet 1.

6. Adjust the dimensions of the graph to make it the way you would like it.  Remove the legend by clicking on it and pressing the delete button (Del).  Generally speaking, a legend is not needed in a plot with only one data series.   The purpose of a graph is to communicate to its intended audience.  Make sure that your graph is clear and that a reader would understand what the graph is about.

7. Add the source of the data used to make the graph.  To do this, look on the drawing toolbar (if you don't have the drawing toolbar on your screen, select it under the menu item View then choose Toolbar then Drawing).  Select the Text Box tool (it looks like a piece of paper with an "A" on it).  Draw your text box and type "Source:  http://www.crh.noaa.gov".

Your graph should look something like this:

Creating Pie Charts

Open the file IL_Pop_By_Race.xls. This file shows the population of Illinois in 2000 classified by race.

a.   Pie charts are used frequently to graphically display the percentages of various categories that make up a whole. Excel can make them very easily. Let's use Excel to make a pie chart of the Illinois data. Select the data in columns A and B. (Do not include the headers.) Click on the Chart Wizard button in Excel. You will get a menu like

Choose the chart type Pie. Press next and follow the instructions. Be sure to add percentages to your pie chart (found under the data labels tab).  Don't forget to increase your percentages to two decimal places (click on any one of the percentages and then click on the increase decimal button).  Be sure to add your data source.

Your pie chart should look something like this:

Creating Bar Charts

Open the file DePaulMajors.xls.   This file shows the number of majors in five subject areas in the years 1999 and 2003.

a)  Use the Chart Wizard to create a column chart of this data.  (What Excel calls a "column chart" is just a special case of what is usually known as a "bar chart".) 

b) Under step two, be sure to click on the series tab to label each data series (which then appears in the legend).  Click on Series1 in the series box and then type 1999 in the name box (see picture below).  Repeat again with Series2 (click on Series2 then type 2003 in the name box).

c)  Continue by adding a title, labeling the x-axis and y-axis, and adding the data source.

Your chart should look something like this: