points on a trendline

  • Thread starter Thread starter Bryan Kelly
  • Start date Start date
B

Bryan Kelly

I have an XY chart with time on the X asis and two or more plots on the Y
axis.

Some of the plots are not very smooth so I added a trend line.
When I move my cursor to some point on the plot line, I get a
little popup window that provides the X and Y coordinates for that point.
When I do this for the trendline, I only get the name of the line. I want
to know the X and Y coordinates of any given point along the trend line.
I want to draw a simple vertical line through a given point on the trend
line
and see where that line intersects the other plots. How do I do this?
 
Bryan -

The trendline does not have points, as such, since it represents a best
fit through your data. You can characterize the trendline readily
enough, though. If it's a straight line, you can use INTERCEPT and SLOPE
in the worksheet, and knowing these, you can determine Y for any X (and
vice versa). If it's a poly fit, you can use LINEST according to Bernard
Liengme's technique:

http://www.stfx.ca/people/bliengme/ExcelTips/Polynomial.htm

- Jon
-------
Jon Peltier, Microsoft Excel MVP
Peltier Technical Services
Tutorials and Custom Solutions
http://PeltierTech.com/
_______
 
The tend lines I am using are never straight and are continuously changing
in slope. The LINEST is far more complicated than what I need.

Thanks for your help.
Bryan
 
LINEST gives you the coefficients of the trendline (except in some
extreme cases where it can be wrong). It might be more *work* than
what you want but other than analyzing the coefficients of the
trendline (a lot of work in itself), it is the only way to get what you
want.

--
Regards,

Tushar Mehta
www.tushar-mehta.com
Excel, PowerPoint, and VBA add-ins, tutorials
Custom MS Office productivity solutions
 
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