Hi all. I hope one of you can help me with this.
I've created a bubble chart to show some data that I have. I now want to show a fitted (straight) line through this. I can do this with the built-in facility in excel, but this just fits the line as if it were an ordinary scatter plot. I want it to take account of the size of the bubbles as well. (The technical term is to do weighted least squares rather than ordinary least squares).
Excel doesn't have any functions built in that will do WLS. So I searched the web and found the addin at http://www.mrflip.com/resources/ExcelFunctions that will calculate the fitted line.
But the problem now is that Excel won't let me add the line because this would need to be as a mixed chart and it says bubbles can't be mixed with other chart types. Agghh!
Can anyone help? My last resort is to just draw a line on and try to get it in the right place, but that isn't very elegant.