To add an extra attempt for an individual student, click the Options icon [1], then select the Show Student Quiz Results link [2].
Select Student
Under the heading Students who have taken the quiz, click the name of the student.
Note: To give an extra attempt to students who have not taken the quiz, you need to add an attempt by moderating the quiz.
Allow this Student an Extra Attempt
Click the allow this student an extra attempt button. The student will automatically receive an extra attempt for the quiz.