The ICH states that when determining the LOD of a method, the residual standard deviation of a regression line may be used as the standard deviation. The formula is: LOD = (3.3xsd)/Slope where sd = std deviation. How is the residual standard deviation determined/calculated? I have used the regression analysis in Microsoft XL's data analysis. It generates a nice report, but I am not sure if it is generating the residual standard deviation.

Thanks
Shawn (the non-statistician)