In article <[EMAIL PROTECTED]>,
dennis roberts <[EMAIL PROTECTED]> wrote:
>this discussion is interesting ...
>there seems to be TWO general kinds of "grading" on the curve ... it would
>be interesting to try to "estimate" how frequently each happens ...
>1. LOWERing cutoffs ... thus, INcreasing the #s of those getting various
>higher grades
>2. making cutoffs such that the distribution of GRADES resembles a normal
>distribution
>i assume that #1 occurs much more frequently and, from my perspective,
>there is NO good rationale for doing #2 ... unless one assumes that ability
>within a class is normally distributed AND ... and far more crucial ...
>that achievement SHOULD resemble the distribution of ability ...
Something like #2 occurs far too often. But either one of these
defeats the value of a grade in indicating anything about what
the student has accomplished.
NOTHING is normally distributed, so grades should not be.
Also, classes are not equal; even different sections of the same
course in the same term are not equal. Trying a different approach
to teaching may well change the distribution of the amount of
knowledge, and thus should change the distribution of grades.
Only absolute grading is a meaningful assessment of what the
student has accomplished. Relative grading almost forces
levels to go down. The American undergraduate grades in the
strong mathematics courses preparing for graduate work are
essentially meaningless at this time.
>in any case ... instructors are suppose to give students some reasonable
>description of the grading system used ... at the BEginning of a course ...
>which i assume would include some facimile of a grading scale ... or what
>one has to do to earn certain grades ... and in this context, i would think
>that anyone who might 'consider" RAISING cutoffs so that FEWER students get
>higher grades ... would be challenged from students .. as this appears to
>border on unethical practice ...
One is not required to go that far. Saying that you will give
your best assessment of what the student knows and can do, based
on scores given on various items, meets the legal requirements.
I do not use a linear grading method; fortunately, early in my
teaching, I had a student put it all together on the final.
>At 02:32 PM 12/22/99 -0500, [EMAIL PROTECTED] wrote:
>> I never, as a teacher, used any curving
>>procedure to lower students grades!
--
This address is for information only. I do not claim that these views
are those of the Statistics Department or of Purdue University.
Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907-1399
[EMAIL PROTECTED] Phone: (765)494-6054 FAX: (765)494-0558
