As a preliminary investigation for the release of a top-secret project, your company has asked you to determine the spring constants for a collection of reference springs. Fortunately, the measurements have already been carried out and you have only to interpret them.
Recall that spring displacement is governed by Hooke's law,
F = -k x
where x is the observed displacement and F is the corresponding required force. Since it is experimentally easier to use mass instead of displacement, the data sets instead specify mass, related by
F = m/1000 * g
where m is mass in grams and g is acceleration due to gravity. Thus the spring constant k may be determined from the experimental data as the slope of the line fitting displacement and force data.
The data are recorded in the format [ m x ]; that is, the mass in the first column and the displacement observed in the second.