OBR -

Here are two of the usual problems with sixth-order polynomial curve
fitting:

(1) Overfitting. You may get a good fit to historical data, but it is
unlikely you can use it reliably for prediction.

(2) Numerical precision. With today's date, you're computing 39573^5. The
result has at least 23 significant digits, but Excel can handle only 15.

- Mike Middleton
http://www.DecisionToolworks.com
Decision Analysis Add-ins for Excel



"OBR" wrote in message
...
I performed a polynomial regression with dates and flow rates in Excel.
The
result provides me wit a sixth degree equation in function of dates
(independent variable). For some reason, when I use the equation to
predict
future flows the equation produces very large values. I am assuming it is
due
to the numerical format of the dates in the cells. Does any one know how
to
solve this issue?