I think this will work for you if you wwant to show only the trend line for
the average but not the average itself.

set up a data set for the average you want and plot it.
add the trend line for this data set.
select the data set on the chart and set line and symbol to none.
If you are using the legend, select the line for this added data set ion the
legend and clear all

"SWeyer" wrote:

Hi all,

I am trying to chart two data sets on a single graph. Using XY scatter, I
can easily graph the data sets (X is time and Y is value in $). My question
is, is there a way to add a trendline that will track the moving average of
the two data sets over time? I have thought that perhaps I need to use a
combination graph, but wanted to hear what the experts out there thought.

Thanks for your help.