AUTOMATA EXAM 1
                     
                       X
                       X     X
                       X     X
                       X     X
 number                X     X
of exams               X     X
                 X     X     X
                 X     X     X
                 X     X     X
                 X     X     X
           X     X     X     X
     X     X     X     X     X     X
     X     X     X     X     X     X
   ------------------------------------
   41-50 51-60 61-70 71-80 81-90 91-100
                  grades

The histogram shows the distribution of grades.