Nevertheless, please LMK what version(s) of Excel you use, in case it is needed for any follow-up discussion. But I do not believe that is germane to your question. older versions Excel like 2010, which I use. There has indeed been a change in how the trendline R^2 is calculated in Office 365 Excel and other recent versions of Excel vs. But I get the sense that you are very capable of filling in the details wrote originally: ``Can anyone point me to the updated equation used to define r-squared in a nonlinear trendline?`` I will try to be brief, because there is a lot that I could explain, but I want to 'rush ahead' to answer your question. And I apologize in advance for my denseness.) (If I have missed an important point, and you want assistance, feel free to explain the intent of columns F:L.

The following refers to my 'new' worksheet. So I have taken the liberty of redesigning the worksheet. Unfortunately, I do not understand what you are trying to do in columns F:L. And it makes it easy to switch between new random data and one or more snapshots. That ensures that we all see the same example. The advantage is: when we find the example that we want to discuss, copy-and-paste-value column N into column O, and change column B to reference column O with formulas of the form =O2. In a nutshell, the random data is created 'on the side' (column N), and initially, the actual data (column B) references column N with formulas of the form =N2.

So just right-click the tab and click Unprotect, if you wish. Note: I 'protected' the worksheet so that I don't modify it accidentally. May I suggest an improvement? See the highlighted changes that I made in the 'orig' worksheet in the attached file. And I'm happy to find someone (else) who knows how to create credible examples with 'random noise'.

Excel get equation for trendline