Regression Line of two sets of data

Hello,

I have a small problem... I have two groups of data plotted in a same XY scatter chart. Now I need to put a regression line, but how can I put it?
I mean, I have two sets of data, but it does seem that I can have a regression line (by right-clicking on the data) for only one set...

I hope it's clear...

Many Thanks

Pitto

Are you saying that you want one regression line that encompasses both sets of data or one line for each data set?

If you want one for each data set, right click on one of the points and select add trendline. In the dialog box you can choose what type of line you want and which series to base it on. Then repeat, but select the other series.

Hello,

Sorry for non being very clear... I would like to have one line for both sets together, not two lines, one for each set.

Thanks
pitto

Two approaches that come immediately to mind.

a) If you want to use the Chart Trendline feature to generate the trendline, then you will need to combine the two series into one series. You don't give any specifics for how the data are laid out, so we can't really help with this. The basic idea is, if the data aren't laid out in a way that readily lends themselves to plotting as a single series, you'll need to find a way to manipulate the spreadsheet so they can be plotted as a single series. If you want to have to two series still show up on the plot as separate data sets, add this combined series as a third series, but formatted to be invisible (no marker, no line). Then base the trendline on the combined series.

b) Use the regression tools/functions available in the worksheet to generate the trendline (may still require manipulating the spreadsheet so the data sets are combined into a single data set). Then plot the spreadsheet generated trendline as a third series. I generally prefer this option because there is greater flexibility in how I regress the data in a spreadsheet, and because I then have easier access to the coefficients of the correlating equation, which I usually need for some other purpose.

Thanks you!
I fixed the problem by creating two points from the estimated regression line and put the trendline! :D

Ciao!
pitto