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chenming7899

木虫 (初入文坛)

[求助] 如何进行非线性方程拟合?

审稿人提出要采用非线性方程进行拟合。如何用 Excel来拟合?
编辑的话
one should never compare SD nor R2 for fits in different coordinates. Determination of parameters and comparisons of fit quality should be performed for the same definition of data deviation. When common (nonweighted and not orthogonal) LSQ fit is performed for any Y-value (minimization of Sum[(Y_exp-Y_fit)^2]) it corresponds to the assumption of constant statistical deviation of Y (i.e. SD(Y) does not depend on X or Y) with Gaussian distribution. If any kind of data transformation is used to obtain linear plot, then this assumption is no longer valid.
E.g. LSQ in the linear Freundlich plot (log coordinates) corresponds to the assumption that in your system SD(q)/q = const (not SD(q)=const) an d for the linear Langmuir plot (i.e. 4 linear Langmuir plots) it is even more complicated.  The only way is to use non-linear fitting (e.g. with free Solver module present in Excel and Open/LibreOffice) – or better yet, weighted non-linear LSQ - and reserve linear plots for presentation purposes.  

理科出身,没学过。请各位大侠帮忙。
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【答案】应助回帖

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chenming7899: 金币+10, ★★★很有帮助 2013-01-13 16:23:22
csgt0: 金币+3, 欢迎交流 2013-01-14 14:57:17
1.
?????????????????????????Langmuri model ???е????????Freundlich model ????????????????????????????????????Excel?e???????w???????????@?N??????С??x????W????????????
2.
????????????^?}?s????????????????t????????N???????(Origin??1stOpt??Matlab??SPSS??R??Statistica......)?e?????????????M?????????P????????y?????
?????Y????o??????????
[???]?????????????????????????????? ???? 1stopt ????????
?????@?治??Global fitting??
http://muchong.com/bbs/viewthread.php?tid=4586018&fpage=1
1stOpt ?????? - ??????
http://www.7d-soft.com/files/1stOpt%20Manual.pdf

3. ???о??????????????????Z??????????W???????H??
2楼2013-01-11 16:32:46
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