Finding R and electric potential

Hi. I have to get R and electric potential from a given data using the first order polynomial fitting technique (linefit)? What is that? Could you please explain? Thanks

[Image Analyst]

Do you have a formula?

[Star Strider]

I get the impression that a first-order polynomial is a linear regression that could be implemented any number of ways. What I don’t get are the data.

What is ‘R’ in this context? A correlation coefficient, resistance, or something else?