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NonlinearFit Question

  • To: mathgroup at smc.vnet.net
  • Subject: [mg16808] NonlinearFit Question
  • From: "F. Mittermayr" <mitterma at linz.vai.co.at>
  • Date: Tue, 30 Mar 1999 02:35:13 -0500
  • Organization: IBM Global Services - Remote Access Mail & News Services
  • Sender: owner-wri-mathgroup at wolfram.com

I use the example of the online-help of NonlinearFit.

<< Statistics`NonlinearFit`
data = {{1.0, 1.0, .126}, {2.0, 1.0, .219},{1.0, 2.0, .076}, {2.0, 2.0,
.126}, {.1, .0, .186}};
NonlinearFit[data,theta1 theta3 x1 / (1 + theta1 x1 + theta2 x2),{x1, x2},
{theta1, theta2, theta3}]
BestFitParameters /. NonlinearRegress[data,theta1 theta3 x1 / (1 + theta1 x1
+ theta2 x2),
{x1, x2}, {theta1, theta2, theta3},RegressionReport -> BestFitParameters]

This works.
Does anyone know what happens if I use
data = {{1.0,1.0, 1.0, .126}, {1.0,2.0, 1.0, .219},{1.0,1.0, 2.0, .076},
{1.0,2.0, 2.0, .126}, {1.0,.1, .0, .186}};
that means the points in data have one dimension more. The model, the
variables and parameters should be the same as in the example above.

I get different values for the theta. Why? Does these values make sense?

Thanks, Franz
mitterma at linz.vai.co.at





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