Please indicate the level of significance of all regressions. I guess what you plotted is the term b of the linear regression (y=a+bx + e). Please indicate in the text. At the moment is not clear for me. Since this is analysis is based on a sample, then the confidence intervals (e.g., 95%) for a, b and the coefficient of determination (r2) should be clearly stated in they manuscript. Indicate sample size for all your regressions. If the sample is small non-parametric test should be pre fared to parametric ones. Could you also indicate what is the RMSE of the regressions?

LS