For the curious, here's how I turned the numbers into letter grades.

First, the University's instructions as to what the grades mean:

       A: Represents achievement that is outstanding relative to the
          level necessary to meet course requirements.

       B: Represents achievement that is significantly above the level
          necessary to meet course requirements.

       C: Represents achievement that meets the course requirements in
          every respect.  

       D: Represents achievement that is worthy of credit although it
          fails to fully meet the course requirements.

       F: Represents failure.

The grade weights are as on the syllabus.  The lowest homework score was
dropped.  All the lab sections had about the same average, so no
adjustments had to be made to account for TA grading.

The standard grade scale you're familiar with: 90%=A, 80%=B, etc.

There are two ways to curve this.  The "flat" method takes the highest
grade in the course, calls that a "100%", so 90% of that high score is
an A, 80% of it a B, etc.

The second way is to use Gaussian statistics (the old "bell curve").  In
this method, a bell curve is fit to the grades.  The letter grades are
assigned to percentiles based upon the bell curve.

This Gaussian method gave you students the best letter grades, so it was
used.  Besides, you all love old Dr. Gauss and his surfaces so much
anyway.  See below for tables comparing the minimum grade needed to get
a letter grade in the three systems (the percentile column was used to
get the Gaussian grades).  

Note that UMD won't allow grades of A+ or D- (they don't say anything
about F+/- though, hmmm :)  so those would show up on your transcript as
an A or D instead.

In the end, I think the assigned grades meet the textual descriptions at
the top of this page.

Gory details:

Gaussian fit mean 63.9, sigma 13.2
The best grade in the class was 87.3%

   Standard Flat Percentile Gaussian
--------------------------------------- 
 A+  97     84.7     95%     85.6
 A   93     81.2     90%     80.9
 A-  90     78.6     85%     77.6
 B+  87     76.0     75%     72.8
 B   83     72.5     70%     70.8
 B-  80     69.8     60%     67.3
 C+  77     67.2     50%     63.9
 C   73     63.7     40%     60.5
 C-  70     61.1     30%     56.9
 D+  67     58.5     20%     52.7
 D   63     55.0     15%     50.2
 D-  60     52.4     10%     46.9