How do I get a trendline for all data series, instead of just one.
 

I need to retrieve R squared values, and trendline information for all data
series within a block of data. Excel is only letting me get trendline
information on one data series, which is almost useless for me.

Dave Darling -

I need to retrieve R squared values, and trendline information for all data
series within a block of data. Excel is only letting me get trendline
information on one data series, which is almost useless for me.<

You can add a trendline and get R squared for each data series.

If you need a trendline for the combination of several data series, you
could copy data into a column containing all combined data, plot that
combined data series as a separate series, and add a trendline.

- Mike

www.mikemiddleton.com