I want to calculate the R-squared value on chart with an Excel formula. But the R-squared value has to be a 2nd order polynomial.

I think R-squared has already been defined. It is a single number.
Perhaps you could restate your question. Do you mean you want to calculate
the R-squared value for a second order polynomical fit to the data?

Look at the LINEST function.

--
Regards,
Tom Ogilvy

"Metin" wrote in message
...
I want to calculate the R-squared value on chart with an Excel formula.
But the R-squared value has to be a 2nd order polynomial.

Also, for a chart, you can add a trendline and in that dialog specify the
fit to be a polynomial of order 2 and have it display the R-squared value
(second tab in the dialog).

--
Regards,
Tom Ogilvy

"Metin" wrote in message
...
I want to calculate the R-squared value on chart with an Excel formula.
But the R-squared value has to be a 2nd order polynomial.