Excel 2007 provides Trend Equations, on charts, fitted to the Chart data. If
you were to take the equation with it's coefficients, plug in the x-axis
values from the data you should be able to regenerate the equation. When the
equation is plotted using the identical chart scale as the original data they
should match. They do not all match. The first and second degree Eq's. do
match, even at higher x-values. However, the fifth and sixth degree Eq's
match at lower values of x but not at higher x-values. Has anyone tried this?
Does Excel 2007 use a least squares method or some sort of a spline method to
determine the Trend Equations? Will appreciate any help.
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rdb