This comes from Instructor Michael Knichel:

The only way to view multiple attempts for a student on a quiz is to go to the quiz and click on the Gear. Then select "Show Studentt Quiz results". This displays a list of students. If you click on a student, you see any and all attempts taken and the score. Once you view the quiz/quizzes, there is no way to go "BACK" to the previous page. You need to go back to the quiz then click the gear again.... There should be a way to move through all the students like in the speed grader.