Since students cannot access the reports section in New Quizzes, they cannot view this sort of information. 

However, if you are referring to the grade distribution graphs found in their individual gradebook (see screenshot titled "grade distribution graph example"), you would need to check the box for that particular setting in the Settings menu of your course. This is labeled as: "Hide grade distribution graphs from students" -- see screenshot titled "hide distribution graphs settings" for this item. Directions to do this:

1. Enter your course
2. Click on "Settings" in the in-course navigation
3. In the "Course Details" tab (this is the default it opens to), scroll to the bottom
4. Check the "hide distribution graphs" box
5. Click on "Update Course Details"

If you don't see the option to do this, or you cannot do this, talk with your organization's LMS admins -- they will either help you find it or let you know why you cannot find it.