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Christian_88
Netherlands
2 Posts |
 Posted - 04/16/2025 : 04:58:28 AM
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Dear All,
I am new to ORIGIN and therefore I hope you can help/explain me.
I need to perform a simple 3rd degree polynomial fit to my data:
X
15.875
9.525
3.175
-3.175
-10.525
-16.875
-23.225
Y
0.411
0.555
0.67
0.728
0.727
0.664
0.547
err_Y
1E-3
0.002
0.002
0.002
0.002
0.002
0.002
The fit has to be done on Y, considering the err_Y. To do that, I follow the recommendations of using "instrumental" and "reduce Ci-sq" (as options). By doing that, I obtained the fit coefficients and their related uncertainties.
Now, I increased the error_y by 100 (i.e., 2 order of magnitude). I am expecting that this has an impact on the uncertainties of the coefficients. However, nothing change and the uncertainties stayed the same.
What am I doing wrong/not getting? Why the uncertainties on the fit coefficients do not change if the error on the points increased?
Thanks for your help!
Christian Fedon |
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Uncertainty on estimated fit coefficients
