NonlinearFit - Logistic Function-CalcCenter3
- To: mathgroup at smc.vnet.net
- Subject: [mg60443] NonlinearFit - Logistic Function-CalcCenter3
- From: Oddur Bjarnason <oddur.bjarnason at broadpark.no>
- Date: Fri, 16 Sep 2005 03:50:36 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
I can fit a logistic function of the form
a/(1 + b*Exp[-c*t])
to the data points -0.06 -0.05
0.97 -4.2
1.99 -9.79
3 -12.44
3.99 -14.57
5.92 -16.85
7.87 -17.27
11.89 -17.69
15.8 -17.74
19.74 -17.77
23.67 -18.19
I can not fit the same function to the data points
-0.08 0.05
0.96 -3.19
1.93 -6.4
2.98 -10.32
3.97 -11.8
5.92 -13.98
7.88 -14.12
11.85 -15.34
15.79 -14.61
19.7 -15.43
23.67 -15.83
I have tried to do it with Mathematica without success.
I have no problem when I use a progam called CurveExpert.
Regards, Oddur Bjarnason