Creating Boundary Curves in Excel?

[Robert H]

I am trying to boundary lines on charts in Excel. For example: If I have
one trendline already on the chart, I want to be able to create boundary
lines based off the original trendline for production purposes. Is the
ability to create boundary lines possible in Excel? Thank you.

Sincerely yours,
Robert Hicks

 

[Andy Pope]

Hi,

You will need to plot extra data series based on the trendline formula.
To get the formula have a look at these sites
http://www.stfx.ca/people/bliengme/ExcelTips/Polynomial.htm
http://tushar-mehta.com/excel/tips/trendline_coefficients.htm

Cheers
Andy