Charts and graphs provide a visual means of interpreting data.

Excel is pretty good at producing useful charts.  While you can usually get the type of chart that you need, you generally have to modify the appearance of a chart produced by Excel to meet even minimal design criteria.  Fortunately, Excel provides the tools to make the needed modifications.

You'll see how to make charts and modify them so that they are good communication instruments.

There are three general designs.

These designs are called "bar charts," "pie charts," and "XY graphs" or "line graphs."

Note that Excel calls vertical bar charts "column charts."  That's not a very common name.  Fortunately, this won't be confusing since you'll see diagrams that show what will be produced when you need to choose between the general chart designs.

There are four steps involved in creating any chart in Excel.

First, you need to have the type of chart you want to build in mind.  How do you know which type?  If you are a beginner, you'll probably be told which type to create.  Otherwise, you should look for examples of how other people have portrayed similar data.  Make your chart like the one they created.

Then you need to arrange your data in Excel so that it is appropriate for the type of chart.

You are then ready to use the Chart Wizard.  It will take you through the basic steps.

Finally, you will need to look at your chart carefully.  It will likely need some modification so that it properly shows the information.  You'll need to use some of Excel's tools to make the needed changes.

Let's go through these steps.

In general, you use bar charts to compare categories.  This is a very commonly used chart design and the one that you are most likely to need.

Pie charts show proportions.  If your data add up to 100%, for example, a pie chart might be useful in showing the relationships between the values.

Paired variables, such as a father's height and his son's height, work well with an XY graph.  That's the design that shows the relationship (or correlation) between the two variables.

You need to choose which of these designs you will use.

Each chart design has a different data arrangement.

A bar chart requires that you have your data arranged in two columns.  The column on the left holds the "category" values and should have the name of each bar. These names will appear at the base of each bar.

The column on the right has the values.  They will be shown as the height of the bar.

Be careful.  You should not have too many categories.  The maximum is about a dozen.  If you have more, you should probably aggregate your data.

An related design is to have pairs of bars, each relating to a category.  In this example, the values in Set 1 are shown in green and those of Set 2 are shown in orange.

The members of each set (that is, a green and orange pair) are arranged next to each other.

Not only should you have not too many categories, you should also not have too many sets (just two or three, maximum).

Data for a pie chart are arranged like those of a bar chart with a single set of bars.

You don't want to have too many slices (probably 8 or fewer).

Although your pie chart will show relationships such as percentages, you should have the actual data values in your worksheet.  Excel will calculate the percentages automatically.

Finally, with a XY graph, you arrange the values with the related pairs as adjacent columns.

Unlike the previous chart designs, with the XY graph you are not limited to the number of points you can put on the chart.  You can have many dozen sets of values.

As you get ready to start the Chart Wizard, you'll first want to select the region of your worksheet that holds the data.

Then you start the wizard.  You can start it from the icon on the tool bar (see the icon on the slide) or choose it from the "Insert" menu.

The first thing that you'll be asked to do is to choose which type of chart.  You will then click the "next" button and follow the prompts.

The result of using the Chart Wizard is a "draft" chart.  I call it a "draft" because it needs modifications before it is finished.

This example shows some of the needed changes.

The title is not appropriate.  The legend isn't needed.  The gray background should be white.  There Y axis needs to be labeled.  Finally, the bars are too narrow and need to be widened.  (Actually, there is even more that needs fixing, but you get the idea.)