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how to enter the initial value for parameters when fit a nonlinear model

desertrose

Community Member

Joined:

Aug 14, 2013

Hello,  I have a question about nonlinear model fit. For example, here is my data set is attached.

x   y

0.8611.000
0.7751.082
0.6861.007
0.8960.985
0.7961.007
0.6901.000
0.9170.971
0.8070.977
0.7220.970
0.7140.898
0.5870.774
0.4560.564
0.4480.384
0.3210.191
0.2010.115

I know it fits this model.

Y=1/(1+A*(EXP(B*X))

When I use JMP 10 to fit the model, I am stuck at the step what number should I enter to give an initial value for the parameter.  I gave some numbers. It does run. Also, after I hit go, there is no plot. Can anyone help? Thanks a lot!

1 REPLY
stevedenham

Community Trekker

Joined:

Jun 23, 2011

That's a logit there, so you can fit logit(Y) = a' + bx, and the values to insert for A will be exp(a') and for B, simply b.

Good luck.

Steve Denham