[R] Compare parameter estimates of a nlsList object

[Jens Currie]

Hello together, 

Is there a tool to test the statistical differences between parameter estimates
of an nlsList fit, with more than two groups? I am able to complete the nlme
function for two groups after getting starting paramaters in nlsList, as seen
below. 

>fit.nlme <- nlme(rate ~ SSmicmen(conc, Vm, K), fixed=Vm+K~state, groups=~state,
start=c(212, -52, 0.06,- 0.01), data=Puromycin) 
>summary(fit.nlme)

However, I am unable to test the differences between more than 2 paramaters. My
data set has 5 different groups and therefore has 5 different paramaeter
estimates and I am not sure how to fill in the start=c() for more than 2
groups.

Thanks 

Jens