dealer evaluation

[Guest]

I have long database of our dealer network and I like to grade them. The
methodology I like to use is to create a normal distrubition curve and
eliminate the worst performing (leftmost part of the curve) 10% in any given
area. Then I like to graph the market and show the boss how we graded the
channel. I assume one of the functions coming with the "data-analysis" Add-in
should do this but I could not figure out how.

 

[PC]

If I recall my statistics correctly, a "score" that is in the bottom 10% of
dealers would be less than -1.2817 standard deviations from the mean of all
scores. One way to calculate that is. There probably is an XL function
that does this, just not sure which one.

=((Dealer Score - Average Score)/ Std Dev Scores)<-1.2817

PC