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There were 11 full-length labs, plus two parts to lab 12. Thus, there were 35 lab parts (11 labs of 3 parts each, plus 2 parts of lab 12). So the total number of points for the labs was 350. As per the syllabus (md), labs counted for 45% of the final course grade.
Each midterm counted for 15% of the final course grade, even though the total number of points on each midterm was different. The final counted for 25% of the final course grade.
This grade breakdown (how much each part counts for the final grade) is as listed on the course syllabus (md).
For exam 1 (average was 67.3%), we promised a curve of "10 to 15 percentage points" (source). Let's assume that means 12.5 percentage points. This exam was worth 15% of the final grade, so 15% * 12.5% = 1.875 points added to your final course average due to this exam curve.
Apparently we never stated a curve (in the daily announcements) on exam 2 (average was 70.1%), but we always intended for a 10 percentage point curve. This exam was worth 15% of the final grade, so 15% * 10% = 1.5 points added to your final course average due to this exam curve.
The average on the final was 81.0%, so there is no curve for that exam.
Thus, there was a total of 3.375 points added to your final course average due to the curves on the midterms. We'll round that up to 3.5 points.
Yes, we round grades. Note that round(x) == floor(x+0.5). So instead of adding 3.5 (from above) and rounding, you can just add 4.0 and don't round. But doing it this way means that rounding has already happened, so if you get an 89.9999999999999999999, it's still a B+, no matter how many times you ask - you don't get to round a second time (in reality, it was an 89.49). Alternatively, you can add 3.5 and then round -- either way will yield the same result.
There is 3.5 points from the two midterms, and no curve from the final. The lab grades were relatively high, so no curve for those either. Adding in 0.5 points yields a total curve (without rounding) of 4.0 -- or a curve of 3.5 and then round.
As stated at the beginning of the semester, each 10-point "decade" is a separate letter grade range (60-70 is a D, 70-80 is a C, etc.). The exact ranges are below. Take your average from the course gradebook and add 4.0 for the curve (or add 3.5 and then round), then see where the result lies on this table.
| Minimum course average | Letter grade |
|---|---|
| 60 | D- |
| 63 | D |
| 67 | D+ |
| 70 | C- |
| 73 | C |
| 77 | C+ |
| 80 | B- |
| 83 | B |
| 87 | B+ |
| 90 | A- |
| 93 | A |
| 100 | A+ |
Recall (again!) that rounding has already been taken into account! Thus, the cut-offs listed above are hard cut-offs.
Note that the A+ range follows a different algorithm. The A+ range is a percentage of the class (the top 6 people, which ended up being an (uncurved) average of 96.0 or above). A (curved) 60 is the minimum passing grade for a D-. You must receive a C- (70) or higher to take CS courses that have CS2150 as a pre-requisite.
There were 13,553 lab grades determined this semester -- this roughly 384 (the number of students) times 35 (the number of graded labs). (The difference between them is for grades that were re-done, or students who dropped.) There were 441 regrades submitted this semester, which is 3.25% of the number of grades determined. Of those regrades, 163 (37%) were due to extensions, not an issue with grading. Of the 278 that remained, 67 resulted in no grade change. Thus, only 211 graded lab parts -- 1.56% of the total grades determined -- necessitated a regrade.