Hi,

In two helper columns, copy the x- and y- data of the first data-set; now
copy the second data-set and paste it below the first data-set in those
helper columns. Make an xy-scatter plot for the combined data (helper
columns) and obtain the trendline.

If you prefer to have the two sets plotted as separate series, maybe for
other purposes, format Series 1 (the combined series) with "None" for "Line"
and "None" for "Marker" (This action would hide the data-points in the
combined plot), and add two more series using the original data.

Regards,
B. R. Ramachandran

"Prba" wrote:

Hi,
I have two series but I want one (common) regression line for both, not one
for each. Is that possible?