Available overrides include:
Enabling this setting would force the memberts of this group to enter a password before being able to access the Quiz.
Open the quiz
Editing the dates under the 'Open the quiz' section will change when the Quiz opens for the members of the group you have selected.
Close the quiz
Editing the dates under the 'Open the quiz' section will change the closing date for the Quiz, for the members of the group you have selected.
This is the most commonly used override. You would edit this setting if you wanted to allow the members of your group more time to complete the Quiz than the rest of the cohort.
You are able to edit the number of attempts the members of your group are able to make at this Quiz.
NOTE: you are able to reverse any of these settings at any time by clicking on 'Revert to quiz defaults' from the 'Group override' page.