Any typical chart inserted in PowerPoint contains two types of data — one of these show as the Series within your charts, and the second data type ends up representing Categories. By default, the Series are shown as the individual chart elements — for example as individual columns in a column chart. Also, the Series show up as the Legend for the chart. Categories on the other hand constitute the groups of these individual columns. If needed, you can quickly swap the visual representation of Series and Categories in the chart.
Learn how to switch data for your Series and Categories in PowerPoint 2011 for Mac.

