Setting time restrictions for quizzes

Making a quiz "unavailable actually takes the quiz offline and wipes out any recorded grades associated with it. So how can you "hide" a quiz from student view without rmoving all the grades? The answer is in using the time restriction feature.

Go to the Assessment manager link in the Control Panel.  
Click on set availability for the quiz you have created. This can also be done at the time you are finishing the quiz.  

You will see a screen like this. Note that the options here are for the quiz while it is still unavailable. To set time constraints beyond the :Set time fro quiz:" feature you must proceed to the next screen by clicking on the button next to "Make assessment available."

You can now set date restrictions for when the quiz is accessible to students. Note that this is different than changing the availability of the quiz which would wipe out all grades that have been previously recorded for it. Blackboard makes this confusing by using the word "available" in more than one way. One can also accomplish something similar to the above by removing links to the quiz, or by hiding the folder it resides in as well.