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 Help me global fit or independent fit?		  New Topic  Reply to Topic
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yusu135

Spain
2 Posts
Posted - 08/12/2017 :  07:55:42 AM  Show Profile  Edit Topic  Reply with Quote  View user's IP address  Delete Topic
Origin Ver. and Service Release (Select Help-->About Origin):
Operating System:
Hi
I use this formula
F(x)=(a*exp(-b*x))+(c*exp(-d*x))
the parameters a (0.5), b (-0.02), c (0.5) and d (0.5)
I have selected Auto parameter initialization because I want the program calcule the parameters.
My data is one X and twenty Y.
I have 2 questions:
where is the difference the global fit or independent fit? what is correct?
I understand the independent fit analyze all curves for separate and global analyze all curves together.
My output independent fit have:
Reduced Chi-Sqr similar 0.005 in all curves
Adj. R-Square similar 0.8 in all curves
and une ANOVA for curve an the p value is significative.
I don't understant the chi-sqr
And ai Have this missage
(1) Parameter Initialization was called.
(2) Fitting No.1 Dataset
----------Levenberg-Marquardt-----------
Reduced Chi-sqr = 0,00253824434968
COD(R^2) = 0,80269551337548
Iterations Performed = 11
Total Iterations in Session = 11
Fit converged. Chi-Sqr tolerance value of 1E-9 was reached.

When I use Global fit
I only have one ANOVA and the p value is 0, and the Reduced Chi-Sqr similar 0.003 in all curves and Adj. R-Square similar 0.8
I have this missage
(4) ----------Levenberg-Marquardt-----------
Reduced Chi-sqr = 0,00324618475966
COD(R^2) = 0,89876445796411
Iterations Performed = 17
Total Iterations in Session = 17
(5) Fit converged. Chi-Sqr tolerance value of 1E-9 was reached.

where is the correct analisis

I'm sorry for my explication and I don't know the people undetand my explication

Thanks
Edited by - yusu135 on 08/12/2017 08:12:09 AM

yuki_wu

896 Posts
Posted - 08/15/2017 :  05:39:03 AM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
Hi,

I think you can find the difference between global fit and independent fit here:
http://www.originlab.com/doc/Quick-Help/GlobatFit-IndependentFit

About how to interpreting regression results, please refer to:
http://www.originlab.com/doc/Origin-Help/Interpret-Regression-Result

Regards,
Yuki
OriginLab
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