[R] Nonlinear regression question

[Tatiana Donnay]

Hello,

If I understand good, I can't have p-value for the nls model.

I have 2 vectors. And I'am doing 

model <- nls(crf ~a*(1-exp(-x/b)) + c, data= d, 
              start = list(a=1, b=3, c=0))

and I want to know If my result is significat, if I can't have p-value, how can I know it?

Thank you