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David.Al
2 Posts |
 Posted - 09/01/2014 : 08:23:12 AM
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Origin: 8.5.0G SR1
Hello!
I did a multiple regression with 1 dependend and 3 independend columns.
When I want to create a color fill contour graph it's just possible to define 2 independend colums for X and Y and the dependend colum for Z.
Is it possible to calculate the values for a fixed third independend colum?
e.g. the third independend column contains the values 10 and 14. Is it possible to calculate the graph with 11?
(I hope it's understandable)
Thank you in advance |
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Echo_Chu
China
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Posted - 09/01/2014 : 11:01:04 PM
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Hi, David
If I understand correctly, you have performed multiple linear regression then you already had
z = a + b*x1 + c*x2 + d*x3.
where a, b, c, d are parameter estimation got from the multiple linear regression.
Then you want to calculate the z value for x3 = 11.
z=a+b*x1+c*x2+d*11
If so, you can calculate the z value with the set column values dialog. You can also look at the links below for more details for setting values using formulae
http://www.originlab.com/doc/Origin-Help/Wks-SetColVal-QuickStart |
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David.Al
2 Posts |
Posted - 09/02/2014 : 08:06:00 AM
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That's very helpful!
To get a easier solution:
Is it possible to "change" or "copy" directly the internal formula of the regression?
I looked for the coefficents of the regression and typed the formula manually, but that's a litte bit complicated...
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Echo_Chu
China
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Posted - 09/04/2014 : 06:25:32 AM
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Hi, David
I am afraid that Origin 8.5 does not support your requirements yet
If in our latest version, 9.1, you can create a user defined function (z = a + b*x1 + c*x2 + d*x3 ) and perform the fitting with the nonlinear curve fitting dialog. The in the nonlinear curve fitting dialog, you can specify existing datasets for x value and z will be calculated after fit.
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Multiple Regression with fixed interpolation