This may help you:

http://groups-beta.google.com/group/...93ac7d4c80271c

"JB" wrote in message
...
Occassionally, when I try to add a trend line to a data series the line is
not displayed on the graph, but a lable appears in the legned box. Any
ideas?

At present I want to add a weighted average trend line and so I am having
to
do it the long way around (i.e., calculate the average values in the
worksheet and then plot them), but this is time consuming.

Any help would be appreciated.