Second, you can the counts of students at different grade points
for Winter 2006 here.
However see also
point 3 below -- you are a stronger class: overall grades will be higher
in Winter 2007.
It is impossible to predict exactly how a class/exam/grades will
finally turn out. This page is to help you understand a bit better how the
system works. If you have questions, feel free to come and talk to me and/or
to your TA.
1. How do we compute a score?
The maximum raw score on the midterm was 48. However, we know
that at the extremes of a distribution, values can be a bit random.
There is no real difference between a student who gets 42 and one
who gets 46: both did GREAT. (There is also no real difference
between a student who gets 2 and one who gets 6, but happily there are
no such students.)
So, first, we rescale to a maximum of 42.
Now the midterm exam is worth 20% of the overall score. I find it easiest to work with a total of 10,000 points, to avoid decimals. So the midterm is 2000.
EXAMPLE: Consider a student who scored 29 on the midterm. This student gets 29x2000/42 = 1381 points towards their overall total. (Or, if you prefer you can think of this as 13.81 percentage points towards the overall 100%.)
If this student did equally well in all components of the class, he/she
would have a total of 5x1381 = 6905 points (Or just over 69%).
Last year, such a student would have ended up with a 2.8 grade on the course.
However, this may not be realistic. Very few students get the same
percent of points on all components of the class.
2. Note the overall score on the course is converted to a grade
``on a curve''.
So, it is how you do relative to the class that also
helps you to interpret your score.
Consider this same hypothetical student who scored 29 on this year's
midterm. This student's midterm score
is at maybe about the 35 th. percentile -- above the
lower quartile, but definitely below the median. Again, if this student
were at the 35 th. percentile on the overall score for the class, then
last year he/she would have had a 2.6 grade overall. BUT READ BELOW
3. Why do we keep class grade percentiles (approximately) constant?
Stat220 is offered to about 650 students every year; about 180 students each Fall,Winter,Spring, and fewer in the Summer. You are a large population. We (the instructors, TAs, and graders) are a small population. So, as we learn in class, there is more variation in us than in you. As a large population, the percentages at each level stabilize-- LAW OF AVERAGES!!
However, classes do vary a bit, and the impression, both mine and the TAs, is that this Winter Stat220 class is a bit better than the ``average Stat220 class''. Thus if anything grades will be slightly higher this quarter than that given by the grade-point percentile from last year. The hypothetical student above, is probably looking at a 2.8 or 2.9 rather than a 2.6.