Have your downloaded Office 2007 SP1 and tried trendlines again?
Download info: http://support.microsoft.com/kb/936982

I was unable to get to your file - my email address was rejected
best wishes
--
Bernard V Liengme
Microsoft Excel MVP
www.stfx.ca/people/bliengme
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"Darren" wrote in message
...
We recently upgraded to Office 2007. When we attempt to do a trendline in
Excel, the order of polynomials is always one below what it is stated to
be
and the highest ordered polynomial is always wrong. (i.e. on a fourth
order
polynomial, it will only display polynomials through the third order and
in
the equation, the third ordered polynomial value is wrong, the others are
correct).

We tried installing the hot fix from KB 938541 as well as right clicking
on
the equation for the chart and adding significant digits under Format
Trendline Label.

A sample file showing the problem can be downloaded from:

https://share.chicagogsb.edu/seos/10...fe4b9af27f96a6

Thank you in advance for any assistance provided.