I assume she intends to move all marks up or down in tandem. I assume too
that the marks themselves are quantitative along some sort of continuum.
Regardless, the easiest thing would be to rank order them and make a decision
where the cutoff lines for A's, B's, etc.make sense. I don't see this as a
statistical problem per se. You could graph the scores with a scatterplot or
histogram to determine the shape of the distribution. She could visually
inspect the plot and see if the distribution is bell-shaped, uniform, skewed,
etc. If the data so indicate, one could do Z scores and find out the distance
from the mean, percentile rank, etc., but IMHO this problem can be better
solved by intuition, viz., looking at the data, drawing rational cutoff lines
and at the same time being fair to the students.
In article <jhD74.6313$[EMAIL PROTECTED]>, "Generic"
<[EMAIL PROTECTED]> wrote:
>My wife wants to adjust marks for a course she is marking. Does someone have
>a formula or something for using a bell curve to move them up or down?
>
>I have done this sort of thing about 15 years ago, but I can't remember any
>of it!
>
>
