From what I understand, the Pearson Coefficient determines if there is a linear relationship between some data. However, doesn't the error from a least squares regression line also do basically the same thing?
I have some points that have around r~=0.90 with error~=15. I also have some other points around r~=0.85 with error~=45. Is there a big difference in meaning between the two? Why is the error rate 3x for only a 0.05 difference in the Pearson Coefficient?