C.4 Building a Pie Chart
The next type of chart we will cover in this lesson is a pie chart. A chart used to compare the parts of a category (expressed as percentages) to the whole. are used to compare the parts of a category to the whole. Typically, each of the parts is expressed as a percentage of the whole. For example, we could use a pie chart to display the percent of people in each level of education attainment. We created a chart of this data in the column chart lesson, but a pie chart of the data might be more meaningful.
The first step in creating the pie chart is to insert a new pie chart into your worksheet. Figure C.19 depicts this activity.
Since a pie chart compares the parts of a single category to the total for that category, there is typically only one data series for a pie chart. In this case, the data series name, "Population", is referenced in cell E5 and the values are the individual percent of people in each level of education attainments in range E6:E12 (Figure C.20).
Pie charts are different from the other charts we have discussed in this lesson because they don’t have a horizontal axis. Instead, the segments, or wedges, of the pie chart are treated as the horizontal axis categories. Therefore, the axis labels are the names of the wedges of the chart. In this case, the wedges are the percent of people in each level of education attainment. The names of the wedges are referenced in range B6:B12 (Figure C.21).
The data sources for the pie chart should look like Figure C.22.
Next, we will edit the title of the chart (Figure 6.21). The title of the chart should be “Education Attainment in the United States.”
The next step in creating this chart is to add data labels to the chart. This can be done using the Data Labels menu item after clicking the plus icon next to the chart. It can also be done by selecting an appropriate chart layout in the Design tab. You may need to scroll through the chart layout options to find the appropriate template. In this case, we are interested in a title centered at the top of the chart, a legend to the right of the chart, and data labels expressed as percentages centered in each wedge of the chart. This layout isn’t always displayed but can be found under the Quick Layout option. Click on the appropriate layout option to update the chart.
The chart now shows the Data Labels on the slices and the Legend on the right side of the chart. Moving the legend to the right allowed the pie to be displayed in a larger size.
The last step in creating this chart is to fix the color on the Graduate or professional degree slice. The black text on the dark blue makes it difficult to read. To fix the color, select the slice by clicking on it twice. The sizing handles will be displayed on only that slice. Choose Fill color on the Home menu or Shape Fill on the Format menu. Select the standard color Yellow as the new fill color.
At this point, the chart is complete.
Displaying Data Labels as Percentages
The default option for data labels is to show the raw values for each of the different categories. Because a pie chart represents the data categories as the percentage of the whole, it generally makes more sense to show the data labels as a percent of the total values rather than as the raw values. The raw data for the “Education Attainment in the United States” chart in this example are already expressed as a percentage, so the values for the data labels do not need to be changed. When you have raw numbers as the source data for your pie chart, you will need to modify the data labels options to display data labels as a percentage.
This is done by double-clicking on one of the data labels on the chart. This will open the Format Data Labels window. Click on the Label Options tab in the window. Uncheck the box next to Value and check the box next to Percentage. This will display the data labels as a percentage.