Be aware of the following:
1. PEARSON() do not calculate correctly in Excel 2000.
- Use CORREL()

In versions of that are Excel earlier than Excel 2003, PEARSON may
exhibit round-off errors. The behavior of PEARSON has been improved in
Excel 2003. CORREL has always been implemented with the improved
procedure that is now used in Excel 2003. Therefore, if you are using
PEARSON for a version of Excel that is earlier than Excel 2003,
Microsoft recommends that you use CORREL instead."
http://support.microsoft.com/default...product=xl2003
(Why do microsoft implement two different version of the same
function?)

"In versions of Excel that are earlier than Excel 2003, PEARSON may
exhibit round-off errors. This behavior leads to round-off errors in
RSQ"
http://support.microsoft.com/default...product=xl2003



2. RANK()
- If you have tieded ranks you need to use a formula like (rank data
in B6:B17)

=RANK($B6,$B$6:$B$17,1) + 0.5*(COUNTIF($B$6:$B$17,"=" & $B6)-1)

or this by microsoft

=RANK(B6,$B$6:$B$17,1) + (COUNT($B$6:$B$17) + 1 -
RANK($B6,$B$6:$B$17,0) - RANK($B6,$B$6:$B$17,1))/2

Excel Statistical Functions: Representing Ties by Using RANK
http://support.microsoft.com/default...product=xl2003


Regards
Nikolai
http://www.pvv.org/~nsaa/excel.html