Eliminating anomalous results in a data range that go into a scatter graph

[steve145]

Hello,

I am working on a spreadsheet that produces a graphical output of students grades, predicted against actual. Currently I am selecting the source range from the two sheets to display the data points on the graph. Would it be possible to eliminate the anomalous results, by this I mean the students that have not achieve any grade. This would be represented by a blank cell in the actual grade sheet. At the moment when this cell is blank the source range of the graph takes this value as 0 and still plots a point. If the actual grade cell is blank then I don't want the graph to plot this point. Can this be done?

Attached is a version of the spreadsheet I am working with.

Stephen