Hi,

Try this:

=RSQ(ln(y-range),x-range) [e.g., =RSQ(LN(B2:B12),A2:A12), where A2:A12 and
B2:B12 contain the x- and y- data respectively]

It seems to me that, while fitting an exponential trendline, the Chart
Wizard actually computes the natural logarithm of the y-values, and performs
a linear fit on the ln(y) vs x data. So the R-Squared value that the
exponential trendline returns is actually the R-Squared value of the
linear-transform. That's why "Help" probably calls it the "transformed
regression model".

Regards,
B. R. Ramachandran

"Sarah" wrote:

I am using an exponential trendline in an Excel Chart and want to replicate
the R-Squared value the chart wizard gives. I know that RSQ would give me
this were I dealing with a linear trend. However, with exponential Microsoft
Help just says a "transformed regression model".

I was hoping someone could give me the equation, or even better offer a
function that calculates it.

Thanks