Adding line to scatter plot

Question

I have a scatterplot of data and would like to add a line to the graph that does not represent the trendline, but rather is of the equation Y = X. My purpose is to show that the points essentially all fall to one side of this line. Is it possible to add such a reference line to a scatterplot?

Answer

Yes, you can but as a workaround! Follow these steps:

• you have to add another column of data
• on that add two values, the max and the min (following y=x).
• once you can see those 2 points on the scatter, just select one and chose Add trendline
• then select a linear trend line

That should fix it up.