[R] nls self starting function

Marlin Keith Cox
Wed, 25 Aug 2010 17:33:10 -0000

I need the simple function for the following set of data.  This is a toy
version of my data, but the error is persistent in both.  To compare with
excel, I would  just 1) format trendline, 2) display equation and
R-squared on chart.

I obviously tried to use a nls and wanted to use the self startup function
SSasymp

rm(list=ls())
t <- c( 0,.1,.2,.7,.4,.5,.6,1,.8,.4,1.2,1.3,1.4,1.5,1.6,
1.6,1.7,1.8,1.9,2.0, 3,6,11)
y<-c(2,3.5,3.01,3.09,3,3.25,3.36,3.49,3.64, 3.81, 4.44, 4.69, 4.96, 5.25, 6,
6.1, 5.89, 6.24, 6.61, 7.00,
12.00, 39, 124.00)
plot(y~t ,xlab="t", ylab="y")
model<-nls(y~SSasymp(t,a,b))
summary(model)
Thanks in advance,
keith


--
M. Keith Cox, Ph.D.
Alaska NOAA Fisheries, National Marine Fisheries Service
Auke Bay Laboratories
17109 Pt. Lena Loop Rd.
Juneau, AK 99801
Keith.Cox@noaa.gov
marlinkcox@gmail.com
U.S. (907) 789-6603

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