Step 1
In the Teach Tab, click on Gradebook in Instructor Tools to open the Gradebook:

Step 2
Select Gradebook Options and select Column Settings in the drop down menu.

Step 3
Select the Gradebook column you want to delete and then select Delete.

Like in WebCT 4.1, a quiz or exam cannot be deleted from the gradebook until the quiz or exam is deleted from the quiz database first.