Hello and thanks for your answer! Exactly something like that, but the question is, does lambda represent the amount of knots for my cubic spline? Edit// Ok I have read now, that your suggestion is a smoothing spline. Smoothing splines are not calculating with knots instead you have penalty function with the factor lambda. So the question is, is there another function in JMP that I can calculate the splines with knots? By the way is there a nice feature how I can extract the formula of the spline regression and calculate "new" height values by just input the weight values? Edit// I think I found a solution. The knotted spline effect should be fine for me, it is hidden under Analyze->FitModel->Attributes To extract formulas and calculate new values, just click on the red red triangle->save columns->prediction formula In the next step just write down the new x-values in the same column were the old x-values are already. The predicted values are displayed in the new column!
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