These are the distributions of scores on the homework, midterm, final, and the total.  (Reminder: total=15% homework, 35% midterm, 50% final).



Then, based on the "total" score, I assigned letters grades "roughly" as follows:

• > 90 A+
• > 76 A
• > 72 A-
• > 68 B+
• > 63 B
• > 60 B-
• > 58 C+
• > 55 C
• > 45 C-
• > 40 D+
• > 35 D

I say roughly because I bumped up letter grades of several students as follows:

• if the combined score was very close to a boundary, e.g, 75.9
  
• if the performance on the final was significantly better than on the midterm
• if the combined score was hurt by a "poor" homework score

These were all judgement calls that go in favor of the students, please do not try to argue your case.