8.01 Preliminary Renormalization of Recitation Quizzes, Fall 1998
November 20, 1998
As was mentioned in the course information sheet, in 8.01 we try
to do the best we can to compensate for the fact that recitation
instructors have different styles in terms of the difficulty of
their quizzes and the manner in which they are graded. We
therefore adjust the Recitatation Quiz grades by a process that
we call ``renormalization.'' Each instructor is calibrated by
comparing the Recitation Quiz grades of his/her students with
their Review Quiz and Final Examination grades (which are
team-graded), and the Recitation Quiz grades are corrected
accordingly. The correction formula guarantees that the
average of the Recitation Quiz grades for all 8.01 students will
either not be changed, or will perhaps go up a little.
To give you preliminary feedback on how to interpret your own
Recitation Quiz scores, we have computed preliminary
renormalization numbers based on the first three Recitation
Quizzes, and the first two Review Quizzes. Since significantly
more quiz data will exist by the end of the term, you should bear
in mind that the numbers presented here are very much subject to
change.
In this document I will give you the formulas for computing your
own renormalized Recitation Quiz grade, and also a set of grade
cuts and a histogram so that you can see where you stand. The
Recitation Quiz grade will count for 20% of your final grade in
the course.
HOW TO COMPUTE YOUR GRADE:
In our effort to be as fair as possible, we are using a fairly
complicated method of computing the Recitation Quiz average.
- STEP 1: Computation of Raw Grade
- To simulate the fact that the lowest of the 5 Recitation
Quiz grades will in the end be dropped, for the preliminary
calculation we dropped the lowest 3/5 of a quiz for each
student who has taken all the quizzes. The dropping a
fractional quiz is accomplished by weighting the lowest quiz
less than the others. The implementation of this procedure
was further complicated by the fact that the Mon-Wed
recitations had 3 full Recitation Quizzes, while in the
Tues-Thurs recitations the last quiz is to count only half.
- Monday-Wednesday sections:
- 3 out of 5 quizzes have happened, so you should drop the
lowest 3/5 of a quiz. That means that one should compute
a weighted average of the three quiz scores, with the
lowest quiz counting as 2/5 of a quiz. Specifically, if
Q1 is the lowest quiz score and Q2 and Q3 are the two
others, then the desired average is:
0.4*Q1 + Q2 + Q3
<Q> = -------------------
2.4
If the grades were not based on 100 as the maximum
possible grade, then you should scale them so that they
are based on 100.
- Tuesday-Thursday sections:
- 2.5 out of 4.5 quizzes have happened, and in the end
you will be allowed to drop one quiz of the 4.5. For the
preliminary calculation, your grade was computed by
dropping the 0.5 quizzes. Specifically, let Q_1/2 denote
the score on the quiz that counts half, and Q1 and Q2
denote the other two scores. I am assuming that the
maximum possible score is 100 for all three quizzes. If
Q_1/2 is the lowest score, then just drop it, so the
average is
Q1 + Q2
<Q> = ----------
2
If Q_1/2 is not the lowest, then let Q1 denote the lowest.
The desired average is
0.5*Q_1/2 + 0.5*Q1 + Q2
<Q> = --------------------------
2
- Students with excused absenses, any day of the
week:
- If you have any excused absences on the Recitation
Quizzes, then
click here
to find out how to compute your raw grade.
- STEP 2: Computation of Renormalized Grade
- We experimented with three different methods of
renormalization, but found that none of them seemed to be
fair in all cases. We have therefore decided to use all
three, and for each student the maximum of the three
calculations will be used for the renormalized grade. For
each instructor, four parameters were determined by
comparing the Recitation Quiz grades and the Review Quiz
grades of the instructor's students. A table of these
parameters is as follows:
TABLE OF RENORMALIZATION FACTORS:
| Sections | Instructor | R | Q | M | B |
| 1 | Busza | 1.276 | 0.580 | 0.990 | 19.2 |
| 2 & 3 | Burgess | 0.916 | 1.526 | 2.185 | -106.7 |
| 4 & 5 | Hauer | 1.037 | 0.913 | 1.093 | -3.764 |
| 6, 7, & 8 | Javan | 0.815 | 2.300 | 1.066 | -22.7 |
| 9, 10, & 11 | Joss | 1.074 | 0.833 | 0.799 | 18.2 |
| 12 | Koster | 1.022 | 0.970 | 0.497 | 40.619 |
| 12 & 14 | Falus | 0.939 | 1.160 | 1.273 | -26.0 |
| 15, 16, & 17 | Burke | 0.868 | 1.641 | 1.445 | -48.6 |
| 18 & 19 | Su | 0.984 | 1.046 | 0.890 | 7.0 |
| 20 | Wiese | 1.111 | 0.774 | 1.115 | 0.5 |
| 21 & 22 | Millar | 1.064 | 0.856 | 1.529 | -32.6 |
| 23 & 24 | Graham | 0.940 | 1.142 | 1.312 | -28.7 |
| 25 & 26 | Katz | 1.204 | 0.673 | 1.103 | 6.3 |
- Use the parameters in the above table to compute your
renormalized Recitation Quiz grades by each of the
following three methods, and then take the maximum of the
three:
- Method 1:
- Renormalized Grade = R * (Raw Grade)
- Method 2:
- Renormalized Grade = 100 - Q*(100 - Raw Grade)
- Method 3:
- Renormalized Grade = M * (Raw Grade) + B
WHERE DO YOU STAND?
The average raw grade for all 8.01 students on the Recitation
Quizzes was 74.1, which I think is very good. Each of the
renormalization methods used is designed to preserve the average
for all 8.01 students, but the ``best of three'' algorithm caused
the average renormalized Recitation Quiz grade to rise to 77.1.
The passing grade for the renormalized Recitation Quiz average
has been set at 60.0, and other numerical grades can be
translated into letter grades according to the following chart:
| NUMERICAL GRADE | LETTER GRADE |
| 87.0 - 100 | A |
| 74.0 - 86.9 | B |
| 60.0 - 73.9 | C |
| 45.0 - 59.9 | D |
| 0.0 - 45.0 | F |
A histogram of the grades is shown below:
RECOMPUTATIONS BEFORE AND AFTER THE FINAL EXAM:
When all five Recitation Quizzes have been given, the
renormalizations will be recalculated based on these quizzes
and the three Review Quizzes. The formula for these
renormalizations will be posted on the web page, in a format
very similar to this document. The grades computed at this
time will be considered ``semi-final,'' meaning that your
grade could go up from this point, but not down.
After the final examination, when the final data is available to
compare the classes with each other, the renormalized grades
will be calculated one last time. If your renormalized grade
is increased by this recalculation, then the new value will
be used; if not, then the value computed before the final exam
will be retained.
IF YOU ARE INTERESTED:
Back to the 8.01
Home Page.
Last modified: Friday, November 20, 1998 11:19 am