Polynomial Eq Parameters

[Guest]

I have an x and y data set for which I want to identify the parameters
(a,b,c) in the following second order polynomial equation. What Excel
functions can do this? I can chart the data and use the trendline function,
but I want to automatically calculate the parameters in individual cells that
I can reference in another formula. Thanks, J

y = ax^2 + bx + c

 

[Guest]

I would also like to be able to calculate the R-squared value for polynomial
equation as well. Same as the chart trendline feature produces, but with the
outcome in a cell rather than displayed on a chart.

 

[Bernard Liengme]

Use LINEST as demonstrated at
http://people.stfx.ca/bliengme/ExcelTips/Polynomial.htm
best wishes

 

[Guest]

I would also like to be able to calculate the R-squared value for the
polynomial
equation. The chart trendline feature gives an R-squared, but displayed on
a chart rather than in a cell .

 

[Mike Middleton]

Jay -

Use LINEST as suggested by Bernard. The value of R-squared is one of the
outputs of the LINEST function. See Excel's Help for details.

- Mike
http://www.mikemiddleton.com