How to graph the difference between two sets of data?

Hello,

To give you a little bit of context I'm graphing the data obtained in an experiment about the volumetric flow of water in a container in the presence of a leakage. As far as I know you are able to graph the residuals when comparing to a polynomial fit using the basic fitting tool, just as you can see here:

The things is that I want to know if there's a way to do something similar but between two sets of data. Let's say I have A(Experimental Data) and B(Analytical Data), and I want to use my Analytical Data the same way I'm using the polynomial fit to find the differences between A and B.

When plotting both data, it looks something like this.

I just want to compare from x = 0 to x = 30. Hope I'm making myself clear haha.

Thank you so much in advance!

[Chunru]

Post two sets of data you want to compare.