The numerical problems with the pre-2003 Pearson algorithm are the same as
with the pre-2003 StDev, Rsq, Slope, etc. They have been discussed in the
statistical literature for over 40 years and in these newsgroups for over 10.
You might find
http://groups.google.com/group/micro...a03470e7a1c650
to be useful.
You will find a number of threads where people report Rsq<0 or Abs(Rsq)>1.
In those instances Pearson will show much worse numerical problems than your
simple tests have shown.
For a relatively simple example, put =$C$1 in A1:B1 and =$C$1+1 in A2:B2.
=CORREL(A1:A2,B1:B2) and =PEARSON(A1:A2,B1:B2) should both be 1 for any
numeric value in C1. However if C1 contains 1E8 then PEARSON will give
#DIV/0, and if C1 contains 1E12 then PEARSON will give -1.
Jerry
"James Silverton" wrote:
>
> "Jerry W. Lewis" <post_a_reply@no_e-mail.com> wrote in message
> news:282E2A68-3C55-4A2D-9959-(E-Mail Removed)...
> > Correl is the better choice. In Excel 2003 and later Correl
> > and Pearson are
> > identical. Prior to 2003, they are mathematically equivalent,
> > but Peason is
> > numerically inferior.
> >
>
> Without disputing your analysis, since all my tests seem to
> produce identical results with Excel 2002, can you point me to
> details of why PEARSON is inferior? Perhaps, you might let me
> have some data that would produce different answers.
>
>
>
> --
> James Silverton
> Potomac, Maryland
>
>