How can I increase the precision in Excel's "Display Equation" option
for trendlines?

I am trying to fit a polynomial regression (trendline) to a X, Y
scatterplot I have created.

Excel's built-in trendline function shows a good fit (R2=0.9999) for a
6th order polynomial, however, If I re-plot the data using the
coefficients from the "Display equation" option, the data diverge
significantly.

Apparently, for high order polynomials, you need to have a high level
of precision in your coefficients (many decimal places accurate) in
order to actually re-plot the same curve.

I also tried using the "linest" function as described in Mr. Liengme's
website (http://www.stfx.ca/people/bliengme/E...Polynomial.htm),
however, I can't seem to make this work properly. I can make it
calculate, but the values don't match data.

Any help with this problem would be appreciated.

Thanks
Kevin

PS Here is the equation that Excel displays on my chart;

y = 4E-09x6 - 9E-07x5 + 8E-05x4 - 0.0038x3 + 0.0996x2 - 1.5179x +
45.146

I am using Excel 2004 for Mac (OSX) Ver11.2


--
KevinW
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