Midterm histogram

30 +
   |
   | XX
   |
   |
25 +          ---
   | XX        |
   |           |
   |           |
   |           |
20 + XX        |
   |           |
   | X        ===
   |           |
   | X         |
15 +           |
   | X         |
   | XX        |
   | X         |
   |          ---
10 +
   |
   |
   | X
   |
 5 +

m=18.2 (61%)
s=6.5