[R] Extracting the dispersion parameter

2003-02-23 Thread Edward F. Connor
I have been unsuccessful in extracting the dispersion parameter in SPLUS 
6.1 using

summary or summary.glm(modelobj$dispersion)

from a glm object in which the family was set to quasi. This is the syntax 
given in the manual. I want to write a script to bootstrap the estimate of 
the dispersion parameter, but cannot seem to access that value.

Any suggestions?

Thanks,

Ed






--

Edward F. ConnorOffice Phone415-338-6997
Department of Biology   Lab Phone   415-338-3873
San Francisco State University  Fax 415-405-0306
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Re: [R] Extracting the dispersion parameter

2003-02-23 Thread Uwe Ligges


"Edward F. Connor" wrote:
> 
> I have been unsuccessful in extracting the dispersion parameter in SPLUS
> 6.1 using
> 
> summary or summary.glm(modelobj$dispersion)
> 
> from a glm object in which the family was set to quasi. This is the syntax
> given in the manual. I want to write a script to bootstrap the estimate of
> the dispersion parameter, but cannot seem to access that value.
> 
> Any suggestions?


summary() calculates it, hence it's part of the summary object:
 
  summary(modelobj)$dispersion


Uwe Ligges

> Thanks,
> 
> Ed
> 
> --
> 
> Edward F. ConnorOffice Phone415-338-6997
> Department of Biology   Lab Phone   415-338-3873
> San Francisco State University  Fax 415-405-0306
> 1600 Holloway Avenueemail:  [EMAIL PROTECTED]
> San Francisco, CA 94132 web: http://userwww.sfsu.edu/~efc
> 
> --
> 
> [[alternate HTML version deleted]]
> 
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Re: [R] Extracting the dispersion parameter

2003-02-23 Thread ripley
On Sun, 23 Feb 2003, Edward F. Connor wrote:

> I have been unsuccessful in extracting the dispersion parameter in SPLUS 
> 6.1 using
> 
> summary or summary.glm(modelobj$dispersion)
> 
> from a glm object in which the family was set to quasi. This is the syntax 
> given in the manual. 

What is `the manual'?  If this is an accurate transcription then `the
manual' is incorrect.

> I want to write a script to bootstrap the estimate of 
> the dispersion parameter, but cannot seem to access that value.
> 
> Any suggestions?

Ask on S-news about S-PLUS questions!  You may have meant

summary(glmobject)$dispersion

but as glm is one area where S-PLUS and R differ considerably it does help 
to ask in the correct forum.

-- 
Brian D. Ripley,  [EMAIL PROTECTED]
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel:  +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UKFax:  +44 1865 272595

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[R] expression for simple EM

2003-02-23 Thread Vumani Dlamini
Dear R users,

I know this is the wrong forum for such a question but I need help.

I would like to write down the likelihood expression for a simple EM 
problem. I have one categorical covariate with 5 levels and a missing count 
which can fall in any of the categories. I know the solution to the problem 
but can't seem to get the likelihood expression correct (if it is possible).

Thanks.

Vumani Dlamini, Student
Faculty of Health Sciences
University of Natal
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[R] A Guide for the Unwilling S User

2003-02-23 Thread Patrick Burns
"A Guide for the Unwilling S User" is available at
http://www.burns-stat.com/pages/Tutor/unwilling_S.pdf
(Or click on Tutorials from the main web page.)
This is an improved version of the document that was put in
the same location a few days ago.  It has dropped the "draft"
status, but I am always interested in suggestions for improvements.
The 8 page document has the aim of allowing a novice user
to get some useful work done fast enough that they don't give up.
This could be a student with an assignment, a worker with a
graph to produce before they go home, or a prospective user of
some specific S functionality.  It applies equally to S-PLUS and R.
It may be redistributed as long as there is no more than a nominal
charge for the media.
Patrick Burns

Burns Statistics
[EMAIL PROTECTED]
+44 (0) 208 525 0696
http://www.burns-stat.com/(new home of S Poetry)
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Re: [R] Subpopulations in Complex Surveys

2003-02-23 Thread Thomas Lumley
On Wed, 19 Feb 2003 [EMAIL PROTECTED] wrote:

> Hi,
> is there a way to analyze subpopulations (e.g. women over 50, those who
> answered "yes" to a particular question) in a survey using Survey package?
> Other packages (e.g. Stata, SUDAAN) do this with a subpopulation option to
> identify the subpopulation for which the analysis shoud be done. I did not
> see this option in the Survey package. Is there another way to do this?
>

Not directly.

This only really matters for svymean. For the regression models it's just
a convenience as you can specify a model that has an interaction with the
subpopulation indicator to get estimates and standard errors in the
subpopulation.

For svymean you can use a regression model too:
Instead of a hypothetical   svymean(~x, design=d, subpop=race==2)  do
   svyglm(x~I(race==2)+0, design=d)

I need to work out if there's a general way to handle subpopulations or
whether it needs to be coded on a case by case basis.


-thomas

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Re: [R] grid.grill?

2003-02-23 Thread Paul Murrell
Hi

M.Kondrin wrote:
Why this command does not return grob? What is special about grill and 
what makes it different from axis, lines, rectangles...


Most of the predefined grid drawing functions do two things:  draw 
something and create and (invisibly) return a grob (graphical object). 
This means that they can be used in several different ways: 
"procedurally" just for their side effect (drawing something); or 
"functionally" for the object they produce (e.g., to use in the 
placement or sizing of another object); or both (e.g., to have a record 
of what has been drawn that can be uniquely identified and edited).  The 
default behaviour is "both" so that grid functions appear to work like 
their standard graphics counterparts (i.e., they just draw something).

Functions that call the grid drawing functions can choose to just draw 
something, or they can choose to use the graphical objects from the grid 
functions to produce a graphical object of their own.  Ideally, a new 
function will do the latter so that functions that want to call it also 
have a choice.  But it is easier to write a function that just does drawing.

grid.grill is an example of a function that just does drawing.  It's a 
convenience function that was easy to write.  It should be rewritten to 
produce a graphical object at some stage -- perhaps a good exercise for 
someone learning grid? :)

Paul
--
Dr Paul Murrell
Department of Statistics
The University of Auckland
Private Bag 92019
Auckland
New Zealand
64 9 3737599 x85392
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Re: [R] 4-parameter logistic model

2003-02-23 Thread Thomas W Blackwell
Christian  -

I acknowledge Prof. Bates' answer and his superior knowledge.
But for the first equation you have typed below, theta1 is
clearly the asymptote as x goes to minus infinity, and theta2
is the asymptote as x goes to plus infinity.

The equation you have typed and the excerpt you have quoted
from the book clearly disagree.  I don't know anything about
the function  SSfpl(), inparticular whether it agrees with
the book or not.

-  tom blackwell  -  u michigan medical school  -  ann arbor  -


On Fri, 21 Feb 2003, Christian Mora wrote:

> Dear R users
>
> I'm a new user of R and I have a basic question about the 4-parameter
> logistic model. According to the information from Pinheiro & Bates the model
> is:
>
> y(x)=theta1+(theta2-theta1)/(1+exp((theta3-x)/theta4)) ==
> y(x)=A+(B-A)/(1+exp((xmid-input)/scal))
>
> from the graph in page 518 of the book of the same authors (mixed models in
> S) theta 1 corresponds to the horizontal asymptote as x goes to infinity and
> theta2 the horizontal asymptote as x goes to -infinity. When I use the
> function SSfpl(input,A,B,xmid,scal), I'm not sure why the value of A is the
> lower of the two asymptotes if according to the original function A should
> be equal to theta1 (upper asymptote).. or maybe I'm wrong.
>
> I'll appreciate any comment on this.
>
> Best Regards
>
> CM
>
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Re: [R] Subpopulations in Complex Surveys

2003-02-23 Thread TyagiAnupam
In a message dated 2/23/03 1:19:39 PM Eastern Standard Time, 
[EMAIL PROTECTED] writes:

> On Wed, 19 Feb 2003 [EMAIL PROTECTED] wrote:
> 
> > Hi,
> > is there a way to analyze subpopulations (e.g. women over 50, those who
> > answered "yes" to a particular question) in a survey using Survey 
> package?
> > Other packages (e.g. Stata, SUDAAN) do this with a subpopulation option 
> to
> > identify the subpopulation for which the analysis shoud be done. I did 
> not
> > see this option in the Survey package. Is there another way to do this?
> >
> 
> Not directly.
> 
> This only really matters for svymean. For the regression models it's just
> a convenience as you can specify a model that has an interaction with the
> subpopulation indicator to get estimates and standard errors in the
> subpopulation.
> 
> For svymean you can use a regression model too:
> Instead of a hypothetical   svymean(~x, design=d, subpop=race==2)  do
>svyglm(x~I(race==2)+0, design=d)
> 
> I need to work out if there's a general way to handle subpopulations or
> whether it needs to be coded on a case by case basis.
> 
> 
> -thomas
> 

Thanks a lot for the answer.  Is there a way to get quantiles and 
cross-tabulations in subpopulations? If I think of proportion as mean of 
binary indicator (y: "got milk?"=1), can I use the solution above for 
proportions in subpopulations?
svyglm(y~I(race==2)+0, design=d)
If I create a binary indicator for a subpopulation (men over 50), can I use 
it with svytable?
svytable( ~y+z,design=d)
--anupam.

*
Prediction is very difficult, especially about the future. 
  -- Niels Bohr
*

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[R] time series outbreak detection

2003-02-23 Thread Johannes Schnitzler
Dear all,

i have multivariate timeseries (weekly data).

1)"Moving standard deviation"
With the "filter function" together with "lag" from package ts
it is possible to calculate a moving average for the time series for each
week at once (6 weeks back from the actual week and 12 weeks from the last two
years).
But i also need the associated standard deviations. Is there a function for
this?


2)"Robust Regression"
The time series derives from reported cases due to different pathogens.
Some of them with saisonal pattern. There are huge differences in counts
(depending on the pathogen) from zero up to several hundred counts per week. I
have only data since 2001. I want to realize outbreak detection algorithms (so
far, depending on the pathogen with Standard Deviation / Poisson and CUSUM).
Beforehand i have to "clean" the data from past outbreaks.
Has anybody experience with a rather robust regression model which cuts
former "outliers"?

Thank you very much for advice.


Johannes Schnitzler
Germany Berlin
[EMAIL PROTECTED]

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[R] trellis.datasets help

2003-02-23 Thread David Parkhurst
I've looked every way I can think of for help on trellis.datasets, but nothing comes
up for me.  Please help me find information on what is included, and how to get at
those data.  Thanks.

Dave Parkhurst

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Re: [R] trellis.datasets help

2003-02-23 Thread TyagiAnupam
In a message dated 2/23/03 7:19:07 PM Eastern Standard Time, 
[EMAIL PROTECTED] writes:


> I've looked every way I can think of for help on trellis.datasets, but 
> nothing comes
> up for me.  Please help me find information on what is included, and how to 
> get at
> those data.  Thanks.
> 
> Dave Parkhurst

Look at William Cleveland's web page:
http://cm.bell-labs.com/cm/ms/departments/sia/wsc/index.html
And at the Trellis homepage (see last sentence there):
http://cm.bell-labs.com/cm/ms/departments/sia/project/trellis/software.example

s.html

Hope that helps.

*
Prediction is very difficult, especially about the future. 
  -- Niels Bohr
*

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Re: [R] trellis.datasets help (lattice ?)

2003-02-23 Thread Deepayan Sarkar

Are you talking about lattice ? 

If so, help(singer) brings up the following:



trellis.datasets   package:lattice   R Documentation

Data Sets in the Lattice library

Description:

 These data sets are included to facilitate the same examples as
 S-Plus trellis. (Detailed descriptions of the datasets are omitted
 for now.)

Usage:

 data(singer)
 data(melanoma)
 data(ethanol)
 data(sunspot)
 data(environmental)

Source:

 These datasets are part of the collection of datasets used in the
 book Visualizing Data by Bill Cleveland, and are available at Bill
 Cleveland's Homepage http://cm.bell-labs.com/cm/ms/departments/sia/wsc/index.html> as
 well as in Statlib.

--

which should point you to Bill Cleveland's website and book.


On Sunday 23 February 2003 06:15 pm, David Parkhurst wrote:
> I've looked every way I can think of for help on trellis.datasets, but
> nothing comes up for me.  Please help me find information on what is
> included, and how to get at those data.  Thanks.
>
> Dave Parkhurst
>
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[R] fill prob. in legend

2003-02-23 Thread Jeremy Z Butler




Hi,
I'm trying to construct a legend which has four lines of text and associated 
symbols. The first two symbols need to be normal lines which vary only in 
colour. The second two symbols should have filled boxes. How do I suppress 
the fill boxes in the first two lines?
J.

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[R] Mass: lda and collinear variables

2003-02-23 Thread Till Baumgaertel
hello list,

when I use method lda of the MASS package I experience a warning:
variables are collinear in: lda.default(data[train, ], classes[train])

Is there an easy way to recover from this issue within the MASS package?
Or how can I tell how severe this issue is at all?

I understand that I shouldn't use lda at all with collinear data and should
use "quadratische" (squared?) discr. analysis (by Welch) instead. Or is
this wrong? Could I do this in R? 

Thanks four your help,
Till Baumgärtel






Abos online bestellen. Oder Leser werben und Prämie aussuchen. 
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Re: [R] Subpopulations in Complex Surveys

2003-02-23 Thread Spencer Graves
I'm not familiar with the survey systems, any array or data.frame can be 
subsetted using a logical vector.

For example, let Data = data.frame(sex = ..., age =, ..., ...).  Then,

Sel.fem50 <- (Data$sex=="Female") & (Data$age> 50)
fem50Answers <- FUN(... data=Data[Sel.fem50,])
If you want to do this to many subgoups, consider "split", "by", 
"lapply", "sapply", "tapply", "aggregate", etc.  See Venables and 
Ripley, Modern Applied Statistics with S, 4th ed.

Hope this helps.
Spencer Graves
[EMAIL PROTECTED] wrote:
In a message dated 2/23/03 1:19:39 PM Eastern Standard Time, 
[EMAIL PROTECTED] writes:


On Wed, 19 Feb 2003 [EMAIL PROTECTED] wrote:


Hi,
is there a way to analyze subpopulations (e.g. women over 50, those who
answered "yes" to a particular question) in a survey using Survey 
package?

Other packages (e.g. Stata, SUDAAN) do this with a subpopulation option 
to

identify the subpopulation for which the analysis shoud be done. I did 
not

see this option in the Survey package. Is there another way to do this?

Not directly.

This only really matters for svymean. For the regression models it's just
a convenience as you can specify a model that has an interaction with the
subpopulation indicator to get estimates and standard errors in the
subpopulation.
For svymean you can use a regression model too:
Instead of a hypothetical   svymean(~x, design=d, subpop=race==2)  do
  svyglm(x~I(race==2)+0, design=d)
I need to work out if there's a general way to handle subpopulations or
whether it needs to be coded on a case by case basis.
   -thomas



Thanks a lot for the answer.  Is there a way to get quantiles and 
cross-tabulations in subpopulations? If I think of proportion as mean of 
binary indicator (y: "got milk?"=1), can I use the solution above for 
proportions in subpopulations?
svyglm(y~I(race==2)+0, design=d)
If I create a binary indicator for a subpopulation (men over 50), can I use 
it with svytable?
svytable( ~y+z,design=d)
--anupam.

*
Prediction is very difficult, especially about the future. 
  -- Niels Bohr
*

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RE: [R] faraway tutorial: cryptic command to newbie

2003-02-23 Thread Adaikalavan Ramasamy
c = concatenate / combine 
Try help(c) or under the 'Vector and Assignments' section of An
Introduction to R.

You have to put the folder 'faraway' into c:/.../R/rw1061/library/
where ... is your path to R and rw1061 could be rw1062 ect depending on
your version.


-Original Message-
From: Christoph Lehmann [mailto:[EMAIL PROTECTED] 
Sent: Sunday, February 23, 2003 12:49 AM
To: [EMAIL PROTECTED]
Subject: [R] faraway tutorial: cryptic command to newbie


I am just about working through Faraways excellent tutorial "practical
regression and ANOVA using R"

on page 24 he makes the x matrix:
x <- cbind(1,gala[,-c(1,2)])

how can I understand this gala[,-c(1,2)])... I couldn't find an
explanation of such "c-like" abbreviations anywhere.

thanks for a hint.

another problem: I couldn't load the faraway library, using the
library() command, even though I specified the path, .. do I need to put
library files into a certain directory? I always got an error: Error in
library(faraway) : There is no package called `faraway'


Thanks a lot

christoph

-- 
Christoph Lehmann 
Department of Psychiatric Neurophysiology 
University Hospital of Clinical Psychiatry 
Waldau 
CH-3000 Bern 60 
Switzerland 

Phone:  ++41 31 930 93 83 
Mobile: ++41 31 570 28 00
Fax:++41 31 930 99 61 
Email:  [EMAIL PROTECTED] 
Web:http://www.puk.unibe.ch/cl/pn_ni_cv_cl.html

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RE: [R] Mass: lda and collinear variables

2003-02-23 Thread Adaikalavan Ramasamy
What is the dimension of your data. i.e. how many observations and how many variables 
do you have?

-Original Message-
From: Till Baumgaertel [mailto:[EMAIL PROTECTED] 
Sent: Monday, February 24, 2003 9:41 AM
To: [EMAIL PROTECTED]
Subject: [R] Mass: lda and collinear variables


hello list,

when I use method lda of the MASS package I experience a warning: variables are 
collinear in: lda.default(data[train, ], classes[train])

Is there an easy way to recover from this issue within the MASS package? Or how can I 
tell how severe this issue is at all?

I understand that I shouldn't use lda at all with collinear data and should use 
"quadratische" (squared?) discr. analysis (by Welch) instead. Or is this wrong? Could 
I do this in R? 

Thanks four your help,
Till Baumgärtel






Abos online bestellen. Oder Leser werben und Prämie aussuchen. 
http://www.epost.de/aboservice

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