[R] Nonlinear regression question

Albertus J Smit asmit at cyllene.uwa.edu.au
Sat Aug 12 07:11:09 CEST 2000

```Dear R users

I recently migrated from Statistica/SigmaPlot (Windows) to R (Linux), so
please excuse if this may sound 'basic'.

When running a nonlinear regression (V = Vmax * conc / (Ks + conc), i.e.
Michaelis-Menten) on SigmaPlot, I get the output listed below:

>>>Begin SigmaPlot Output<<<
R = 0.94860969	Rsqr = 0.89986035	Adj Rsqr = 0.89458984

Standard Error of Estimate = 4.1543

Coefficient	Std. Error	t	P
a	34.5878	2.7690	12.4910	<0.0001
b	6.8553	2.2949	2.9872	0.0076

Analysis of Variance:
DF	SS	MS	F	P
Regression	1	2946.6381	2946.6381	170.7350	<0.0001
Residual	19	327.9123	17.2585
Total	20	3274.5504	163.7275
>>>End SigmaPlot Output<<<

(In the above output, a is Vmax and b is Ks)

I have no problem performing the regression using R, and I successfully
obtain the parameter estimates using the function nls().  However, how do I
obtain the ANOVA output, r, r^2 and adj. r^2?

Any help appreciated,
AJ

Dr Albertus J Smit
(Seawead ecophysiology / Stable isotope ecology)
Department of Botany
The University of Western Australia
Nedlands 6907 WA
Tel. 08 9380 2416
Fax  08 9380 1001

-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-help-request at stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._

```