I've got a scattergraph and developed a line of best fit. (For info, it's a
4 order polynomial.)

What I'd like to do is show additional lines on the chart +/- 20% around the
calculated lobf - basically so I can see what points are outside that range.

Is there a way I can do it. Ideally a generic solution would be the best as
the next lobf could as easily be exponential.

TIA

Rob

On Wed, 25 Apr 2007, in microsoft.public.excel.charting,
RFJ said:
I've got a scattergraph and developed a line of best fit. (For info, it's a
4 order polynomial.)

What I'd like to do is show additional lines on the chart +/- 20% around the
calculated lobf - basically so I can see what points are outside that range.

You say you "developed" it. Was this actually in the spreadsheet cells,
or just using the trendline chart feature?

If the former, then create a range of cells that references the first
range and multiplies it by 1.2, and another range that does the same,
except multiplying by 0.8.

--
Del Cotter
NB Personal replies to this post will send email to ,
which goes to a spam folder-- please send your email to del3 instead.

You can get the polynomial coefficients with LINEST(), or directly calculate
points on the polynomial curve with TREND().

Jerry

"RFJ" wrote:

I've got a scattergraph and developed a line of best fit. (For info, it's a
4 order polynomial.)

What I'd like to do is show additional lines on the chart +/- 20% around the
calculated lobf - basically so I can see what points are outside that range.

Is there a way I can do it. Ideally a generic solution would be the best as
the next lobf could as easily be exponential.

TIA

Rob