Gompertz curve

[salvomic]

(03-30-2015 07:44 PM)Marcio Wrote:  BTW, you will have to normalize your data before using any (or most) parameter estimation program or app.

Just like this:
Y:=Y/max(Y). That should only change the value of A, which will have to be multiplied by max(Y) after you get the results back. The values of B and C should and will not be affected by this little trick.

doing so, I get a logistic as 1.1177/(1+0.6269*e^(-0.1929*X)) and it is very close to the observed data. The asymptote should be about 1.1177 (A)...
This curve seems to fit to my data better than the Gompertz (but a book of mine write that those data are from Gompertz curve...)

manually (empirically) I get for Gompertz A=1.1177, B=0.44, C=.14, but also so, Logistic is a little more close to the data...

Now I can see it in Statistic 2var (also if seems don't fit very well)