Excel has two primary types of charts that graph data sets onto an axis: line charts and scatter charts. Depending on your settings, the two types of charts can look identical, but using the wrong one ...

So, select any cell in your formatted Excel table, and in the Insert Tab on the ribbon, click the top half of the split "PivotChart" button.

The X-axis, which is the horizontal axis, on most Excel charts does not use numeric intervals like the vertical Y-axis does. The X-axis contains either strings of text or a date under each set of data ...