Hello, I'm stuck with a chemistry problem as I did not have any statistics course so far and don't really understand the explanations I found online. It's about dating rock and I'm supposed to use the least-squares method to calculate the slope and intercept of a linear isochron. I can solve the problem with any given pair of data, but my results differ quiet a lot when I try to use a least-squares method as described on different websites (so I probably don't understand it, which also shows as I don't quiet know what the result actually represents) Here's a rather random set of data x - y 700 - 17 40 - 2 100 - 3 150 - 4 further given: slope m=e^(labda t) - 1 and t=(1/labda)ln(m+1) labda = 1.4x10^-11 Any help is greatly appreciated lil'me edit: I know that I get the slope as one result and can calculate the time with it. I also know how to calculate the intercept if y=mx+b and mx being the slope and b the intercept. I just don't know which figure to use for y.