Hi, I need to plot a graph of F=kx for my lab report. By measuring x, displacement of spring for every mass (20g, 40g,50g) we found k. Now i need to draw F-x graph. I put my F and x data on graph w/o any problems. But when it comes to draw the line of F=kx i get stuck. Using the line's slope i need to find theoritecal k and calculate the error. I need to have a graph like this: http://phoenix.phys.clemson.edu/tutorials/graph/labgraph.gif This is my second lab report so i need help to get started and learn how to draw properly.