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LIGHSOO
China
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 Posted - 02/10/2007 : 09:23:28 AM
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Origin Version (Select Help-->About Origin): 7.5
Operating System:win xp home
the datas :
c 0.171 0.915 1.74 2.60 3.46 4.32
σ 4.40E-02 3.68E-02 3.08E-02 2.58E-02 2.17E-02 1.86E-02
c 5.14 5.66
σ 1.61E-02 1.43E-02
i want to get the relation of them.
when i use non-linear curve fit to do it in origin, the result is different with that i got with excel, is there anything different between them? |
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larry_lan
China
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Posted - 02/10/2007 : 09:58:39 AM
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Hi:
You'd better tell us how you organize your data, how you fit by Origin & Excel and what's the fitting model.
Larry
OriginLab Technical Services |
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LIGHSOO
China
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Posted - 02/10/2007 : 9:07:26 PM
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| the model i use is y=A+Bx+Cx^2 |
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larry_lan
China
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Posted - 02/10/2007 : 10:56:30 PM
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Well, you can use the Polynomial Tool (Tools : Polynomial Fit) and set the polynomial order as 2. To fit the model, data should be organized by X column and Y column, so maybe you can explain which row is your X data and which is Y. There are six numbers in the first c row and only two in the second c row. If this is all your data, only two (x, y) data points will be used. I really have no idea how you get different result without your detail steps.
BTW, curve fitting in Origin supports Y error only.
Larry
OriginLab Technical Services |
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LIGHSOO
China
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Posted - 02/10/2007 : 11:55:17 PM
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| thanks for your replying, let me have a try. |
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zachary_origin
China
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Posted - 02/11/2007 : 06:13:44 AM
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This article for Excel may explain the problem.
The following is the result I got from Excel and Origin for your data.
Origin
Parameter Value Error
----------------------------------------
A 0.04501 0.00047
B -0.00908 0.00038
C 0.00066 0.00006
----------------------------------------
Excel:
y = 0.000662309 x2 - 0.009085380 x + 0.045017851
Zachary
OriginLab Technical Services.
Edited by - zachary_origin on 02/11/2007 07:04:31 AM |
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why the equation is different.