Hi! I need your help. I read a post in a forum of chromatography about how to determine the appropriate linear regression weighting. The natural log of instrument response was plotted against the natural log of standard concentration. The slope of this line was then used to determine whether unweighted linear regression, linear regression using a 1/x weighting factor, or linear regression using a 1/x2 weighting factor would be used, according to the following criteria: slope < 0.25 = unweighted; 0.25 < slope < 0.75 = 1/x weighting factor; slope > 0.75 = 1/x2 weighting factor. I want to use this criteria in study but I have looked for on the internet and I could not find this criteria anywhere. Does anyone know any article or book where I can find this criteria? or another criteria to select the Correct Weighting Factors for Linear and Quadratic Calibration Curves. Thank you very much!!!!