From the student grade page, you can view the grade distribution of the whole class, as well as specify new grade ranges.
Viewing grades:
By assignment type as defined by your grading scheme:
From here you can look at an individual student's scores by clicking on their name or at their individual submission by clicking on their score.
By student by clicking on their name:
You can reach this page by clicking on a student's name in the course roster as well.