On Dec 12, 9:44 pm, Darren wrote:
SP1 did not fix the problem.
If you run the same dataset under 2003 do you get the roughly the same
coefficients for a 4th order fit as are displayed in 2007 but with one
value hidden. Or is 2007 actually doing a 3rd order fit when you ask
for a 4th order?
If you post an ASCII example of test data and observed fitted
equations 2003 vs 2007 for orders 1,2,3,4 then someone might look at
it.
I am a bit surprised at your claim because I have not seen it
misbehave on 1st order linear fits - the display is y = mx + c as
expected. OTOH most of my stuff was created in 2003 and ported to 2007
so any bugs in the Chart Wizard or user interface would not affect me.
The new polynomial fit algorithm used in charts from 2007 is as dumb
as hell and significantly less numerically stable than previously
(borderline at 2nd or 3rd order polynomials depending on the data).
Previously the charts used a clever regularised algorithm that worked
much better than the generic polynomial fit LINEST in the
spreadsheet.
That may have something to do with your problem.
Bin 2007 and ask for your money back. The product is not fit for
purpose. XL2003 charts are way better.
Regards,
Martin Brown
"Bernard Liengme" wrote:
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
remove caps from email
"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...596e383fd90e46...
Thank you in advance for any assistance provided.- Hide quoted text -
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