Quiz results visibility settings are controlled within the settings of the quiz activity, not in the gradebook.
1. Click on the quiz activity, and in the Administration block go to Quiz administration > Edit settings
2. Open the Review options tab. These options control what information students can see when they review a quiz attempt or look at the quiz reports.
If you enable marks during the attempt, students can see the marks obtained for each question as they go.
If you enable marks immediately after the attempt, students can see their marks as soon as they finish the quiz.
If you enable marks later, while the quiz is still open, students can see their marks a short time after finishing the quiz (5-10 minutes after completion).
If you enable marks after the quiz is closed, students will not be able to see their marks until after you have closed the quiz.
Please click on the question mark beside each feedback type for further information.
Note: Review option settings work in conjunction with the How questions behave setting that sits directly above. Certain question behaviours render certain review questions un-selectable and will auto-select others. Please contact your local eLearning support team for assistance creating quizzes with complex settings.