How can the scores for a quiz be restored? Also how can one enter grades for a quiz manually onto the Grades site?
I'm not exactly sure what you mean by restoring a quiz score, but there is a history kept of all gradebook changes and you should be able to look up any previously recorded scores with it How do I view the history of all grading changes in the Gradebook?
As for entering grades manually, in the Grades are you can manually enter a grade by clicking in the spot where it goes and typing in the grade.
Retrieving data ...