In the first chart you see here, projected sales and actual sales revenues (dollars, not cases) are shown as columns, clustered side by side.
Imagine, however, that you'd like to create a chart to place extra emphasis on the differences between projected sales and actual sales.
A combination chart that uses two different chart types can place just this kind of emphasis on data.
The second chart here combines a Column chart to show actual sales with a Line chart to show projected sales. The difference between projected and actual sales catches your eye more quickly and effectively than in the all-columns chart. Although both charts use identical data, the second chart is clearly more informative.
It's easy to create a combination chart. In this example, you'd click on a column for the projected sales to select all the columns for that data series. Then you'd select a Line chart type in the Chart Type dialog box. You'll see how in the practice session.