Physics lab experiment? Springs?

Question

So I did this lab in my physics class (it's a freshman class, we haven't even taken Calculus yet, I hear that would make it soooo much easier) and I understand none of it, my lab partner did most of it and didn't bother to try to explain it, and anyway we have this graph and oh, we were measuring the spring constant of a single spring, however using different masses hanging off of it, and we have a graph in LoggerPro and it's Force (N) versus Distance (m) and my lab partner sent me the graphs and what's left to do, which is find the 'r' value as well as 'r^2', which I have the tiniest inkling of even what they are. I know it has to be between one and negative one and that the closer it is to either end of that spectrum, the better, but other than that I am completely lost. Does anyone have an idea
a) what I'm going on about
or, hopefully,
b) what I need to do to get said 'r' values?

Answer 1

The force of a spring is k*x, so force versus distance should be a line. Your experimental data is going to have different amounts of error for each measurement, so you have to do a line fit, i.e., linear regression. r is the regression coefficient and the sign of r reflects the negative or positive slope of the line.

http://en.wikipedia.org/wiki/Linear_regression
http://en.wikipedia.org/wiki/Simple_linear_regression

Answer 2

You should have used LabVIEW data acquisition software

Answer 3

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