Trendline Question- Graph with 2 Y Axis

[phil6666]

I have a graph which uses a primary & a secondary Y axis.

The trendline works fine for the series which uses the primary Y axis,
but the series using the secondary Y axis adds a trendline based on
the primary Y axis.

Am I doing something wrong?

thnx

 

[Jerry W. Lewis]

If your question had been clear, you probably would have gotten an
answer when you previously posted it last Monday. Try giving a more
complete description of what you are doing, what is happening, and why
you don't like what is happending.

Jerry

 

[phil6666]

Sorry about that, I wasn't sure how much detail I needed; Thought I
was simply making some basic mistake...

I have a graph set up with a primary and secondary Y Axis.

The range on the primary (left) Y Axis is 0 to 1,800

The range on the secondary (right) Y Axis is 0 to 120.

Both scales are set to "auto."

I added a linear trendline to the data on the primary axis without a
problem.

If I attempt to then add a linear trendline to the data on the
secondary axis, the scale on the right changes from "0 to 120" to
"-100 to 900" and I only show a very "flat" graph of the data without
an apparent trendline!

NOTE: If I remove the "auto" feature, the scale remains the same but
I still cannot add a linear trendline. (When I right-click and
instruct it to add one, nothing seems to change!!!???)

Any idea????

 

[Jerry W. Lewis]

Still not enough information to reproduce the problem.

The axis will expand to contain contain all values on the trendline,
which may extend over a broader range than the data themselves
(particularly if there are x-values that have no y-values); but you seem
to be saying that the resulting scale is huge in relation to the scale
needed for the trendline.

Jerry

 

[phil6666]

Not sure why it helped, but I changed the graph from a "line" to an
"XY (scatter)" and the second trendline seems to work correctly.....

(It was set up as a line graph since both sets of data share the same
X axis values.)

 

[Jerry W. Lewis]

"Line" chart is a misleading title. It has nothing to do with whether
you want a line or not; rather it specifies that the x-axis represents
categories instead of a numeric scale. When numeric x-values are
required (as in a trendline) then they are taken to be 1,2,3,...
regardless of whether x-category labels were provided or not. Changing
from a "Line" to an "XY (scatter)" changes the presumed x-values from
1,2,3,... to whatever x-values you actually supplied.

Jerry