View Single Post
  #3   Report Post  
Posted to microsoft.public.excel.charting
Jerry W. Lewis Jerry W. Lewis is offline
external usenet poster
 
Posts: 837
Default How do I improve Accuracy of trendlines?

Right click on the equation and format to display scientific notation with 14
decimal places.

Also, make sure that your chart is an "XY (Scatter)" chart and not a "Line"
chart. The "Line" chart is very misleadingly named; it has nothing to do
with whether you want a line or not--rather it considers the x-data (if given
at all) to be category labels instead of numbers. Why it offers to fit a
trendline when it does not believe the x-data to be numeric is a mystery; but
when asked to do so, it assumes that the x-data are 1,2,3,... instead of the
values that you may have supplied. As a result, trendlines on "Line" charts
are usually worse than meaningless.

Jerry

"Tom21" wrote:

I am taking known data (4 points) and creating a trendling. I am selecting
the option to show the formula and R*R value, which is 1.0. I am charting
this equation and comparing it to the data used to create the formula, and to
the chart used to derive the formula. They are very different. Can I correct
this situation? If so, how? I have checked to make sure that I typed in the
correct formula. Where do I go from here?