Equation and R-Square Value Remained Unchanged?

Example.xlsx <----- Attachment

I just realised that the equation and R-square value of trendline on my scattered plot remained unchanged when I modified its data.

So what happened was:
1. The plot (scattered plot, with power trendline, equation & R-square) was originally created in a spreadsheet (Sheet 1).
2. A copy of Sheet 1 in the same book was then created (Sheet 2).
3. The data in Sheet 2 were modified. The data points on the plot moved BUT the equation and R-square value remained unchanged.

And what I did was:
1. Deleted the trendline, equation and R-2 and reconstructed them. Results: They were still the same.
2. Deleted the data points and replotted the graph. After that, trendline, equation and R-2 were created. Results: The equation and R-2 magically changed!

you will probably need to upload a sample spreadsheet. I cannot replicate the behavior you describe in my installation. As long as calculation is set to automatic, when the spreadsheet updates, the chart updates automatically, and the trendline parameters update automatically as well.

I don't use the chart trendlines very much -- I usually use the LINEST() function to perform regressions directly in the spreadsheet.

This is interesting behavior, which I have not seen before. After verifying the behavior, the first thing I did was to create a new trendline and display that equation and R2 value. This new trendline equation updated as expected. I noticed that the new trendline label had the equation on one line with a carriage return between the equation and R2. As soon as I edited the trendline label to match yours, the equatioin stopped updating. I then found that if I went in and removed the trendline label from your trendline, then reformatted the trendline to display equation and R2, the new trendline label updated as expected, and was formatted with a line feed/carriage return between the two elements. It seems that, if I do anything to edit the "text" inside of the trendline label textbox, it "breaks" the link between the trendline parameters and the label textbox. I don't really know why this would be the case, but that is what appears to be going on.

IN summary, the solution I see is to delete/remove the current trendline label, then recreate the label from the "format trendline" dialog. Then, leave that label textbox alone.

I might also suggest that, if you need more reliable regression analysis, that you learn how to use the LINEST() and other worksheet functions to perform the analysis in the spreadsheet. Chart trendlines can be easy and, but I find them limited. Thus, I prefer to perform these analyses directly in the spreadsheet (https://support.office.com/en-us/art...rs=en-US&ad=US )