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Access Object's Objects HELP

3 messages · DivineSAAM@aol.com, Sundar Dorai-Raj, Douglas Bates

DivineSAAM@aol.com
# 
Dear WizaRds,

A run of nls produces the following concise summary:
Formula: 0 ~ wt.MM(conc, time, A1, a1, A2, a2)

Parameters:
    Estimate Std. Error t value Pr(>|t|)  
A1 4.814e+02  2.240e+01  21.495   0.0296 *
a1 7.401e-01  7.435e-02   9.956   0.0637 .
A2 1.613e+02  1.738e+01   9.280   0.0683 .
a2 1.770e-02  7.324e-03   2.417   0.2497  

------------------------------------------
I need to access the estimates of A1,a1,A2...

How can I do this?

Also, I need to add a column to Parameters: giving
the ratio of the Std. Error to Estimate. Is there a way to get summary to do this?
I can't find the summary implementation.

I am using R 1.7.0 on Windows XP

HELP! Please:-)

Kind Regards,

Oscar A. Linares
The Geriatrics Center,
University of Michigan
Sundar Dorai-Raj
#
DivineSAAM at aol.com wrote:
Most of the time, you can assign the summary list to a variable and 
extract it that way. As in (using the example on ?nls):

R> x = summary( fm1DNase1 )
R> names(x)
[1] "formula"      "residuals"    "sigma"
[4] "df"           "cov.unscaled" "correlation"
[7] "parameters"
R> x$parameters
      Estimate Std. Error  t value     Pr(>|t|)
Asym 2.345180 0.07815395 30.00719 2.165503e-13
xmid 1.483090 0.08135322 18.23026 1.218535e-10
scal 1.041455 0.03227080 32.27236 8.506916e-14

sundar
Douglas Bates
# 
DivineSAAM at aol.com writes:
Use the coef extractor function, as in
 coef(cs.wt)

In general the best way to get information on a fitted model is to use
the extractor function like coef(object) as opposed to trying to
decide which component in the object holds the information of
interest.  In the case of objects of the nls class you really do want
to use the extractor functions because these objects have an unusual
internal structure.
The "t value" is the ratio "Estimate"/"Std. Error".  Do you really
want "Std. Error"/Estimate?
The nls package now has a namespace so the S3 methods are hidden.
You need to use
 getS3method("summary", "nls")
to see the gory details.