How To Grade 40 Students relitively On a Normal Distribution.
 

I couldnt post a reply to your question for some reason.
In fact Im not even sure exactly what your question is however:
There is an interesting example of nested If functions around grading
results as follows:
A
1 Score
2 45
3 90
4 78

=IF(A289,"A",IF(A279,"B", IF(A269,"C",IF(A259,"D","F")))) Assigns a
letter grade to the first score (F)
=IF(A389,"A",IF(A379,"B", IF(A369,"C",IF(A359,"D","F")))) Assigns a
letter grade to the second score (A)
=IF(A489,"A",IF(A479,"B", IF(A469,"C",IF(A459,"D","F")))) Assigns a
letter grade to the third score (C)

May not be what your looking for but i like it so posted it anyway!
Is what your looking for a formula to show deviation from a pre defined mean
score?