Displaying 20 results from an estimated 9000 matches similar to: "Transforming matrix"
2003 Jan 21
2
books on categorical data analyses
Dear All,
We are about to purchase the second edition of Agresti's "Categorical Data
Analysis" (my old copy of the first ed. of that wonderful book is falling
apart). I would appreciate suggestions about other comparable books which, if
possible, have examples using R/S code (instead of SAS).
Thanks,
Ram?n
--
Ram?n D?az-Uriarte
Bioinformatics Unit
Centro Nacional de
2003 Jan 14
3
PLS regression?
Hi all,
I would like to do some QSAR analysis (quantitative structure activity
relationship). I need to use some Partial Least Squares (PLS) regression,
but I have not seen this option on the R-project. Is it possible to do this
kind of regression on R?
thank you in advance
best regards,
olivier
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2004 Jan 15
4
SIR
Ich habe in R eine Version von SIR gefunden und ausprobiert. Leider kann
diese multivariate Responses nicht verarbeiten. Gibt es in R eine
ausgefeilte Version von SIR?
2003 Dec 11
2
typeIII SS for lme?
To avoid angry replies, let me first say that I know that the use of
Type III sums of squares is controversial, and that some statisticians
recommend instead that significance be judged using the non-marginal
terms in the ANOVA. However, given that type III SS is also demanded by
someā¦ is there a function (equivalent to drop1 for lm) to obtain type
III sums of squares for mixed models using the
2003 Dec 15
2
help in lme
To anyone who can help,
I have two stupid questions, and one fairly intelligent question
Stupid question (1): is there an R function to calculate a factorial of a number? That is...is there a function g(.) such that g(3) = 6, g(4) = 24, g(6) = 720, etc?
Stupid question (2): how do you extract the estimated covariance matrix of the random effects in an lme object?
Intelligent question
2003 Sep 16
1
simplifying randomForest(s)
Dear All,
I have been using the randomForest package for a couple of difficult
prediction problems (which also share p >> n). The performance is good, but
since all the variables in the data set are used, interpretation of what is
going on is not easy, even after looking at variable importance as produced
by the randomForest run.
I have tried a simple "variable selection"
2004 May 03
1
boxplot.formula with missing values (PR#6846)
If an array has missing values in different rows, plotting using the formul=
a=20
interface can produce errors. Example:
fake.data <- matrix(rep(-100:100, 4),
ncol =3D 4)
par(mfrow =3D c(1,2))
boxplot(fake.data ~ col(fake.data))
abline(h =3D 0, lty =3D 2)
boxplot(as.data.frame(fake.data))
abline(h =3D 0, lty =3D 2)
##### Add the missing data
fake.data[190:200, 1] <-
2002 Dec 11
2
Can't find nls()
Hi,
I looked for the nls() function and couldn't find it. In the refman.pdf
it's mentioned as part of the nls package which I cannot find and I also
read something about the MASS package, also impossible to find for me.
Kris
--
------------------------------------------------------------------------
http://perswww.kuleuven.ac.be/~u0027178/VCard/mycard.php?name=krisn
2002 Dec 12
1
Anova
Hi,
I have a microarray matrix 3000x70 for example (genes x
experiments). This data has more than 2 classes. I would like
to make some filtering on the genes. For example, I would like
to exclude genes with the same mean expression across all
classes. This is a problem of ANOVA
H0:mu1=mu2=...=muk
H1: at least one is different
First question: Do you think Anova is reasonable for this?
Second
2003 Feb 14
2
factorial function
Sorry for the stupid question, but is there the factorial function in
R? I tried to find it using help.search('factorial') but got nothing
appropriate.
Many thanks,
-Serge
2003 Aug 26
2
coxph.control
How can I specify the maximum number of iterations in coxph
whilst also specifying my model?? I can't find any on-line
examples. Thanks
2003 Jun 17
2
(no subject)
Hello,
I'm trying to write code for a repeated measures ANOVA. To put things in
perspective, I'll describe my experiment (briefly). I have a 2X2 factorial
design with pH (5.5, 6.5) and local community (present, absent) as my treatments.
I had plastic enclosures that I sampled across five weeks with the density of
7 species acting as my response variables. I'm analyzing one
2006 Jan 04
2
Looking for packages to do Feature Selection and Classification
Hi All,
Sorry if this is a repost (a quick browse didn't give me the answer).
I wonder if there are packages that can do the feature selection and
classification at the same time. For instance, I am using SVM to classify my
samples, but it's easy to get overfitted if using all of the features. Thus,
it is necessary to select "good" features to build an optimum hyperplane
(?).
2004 Feb 09
3
citing a package?
How do I cite a package (not R itself - I know how to do that)? Any
thoughts or links?
Many thanks in advance?
Hank Stevens
Dr. Martin Henry H. Stevens, Assistant Professor
338 Pearson Hall
Botany Department
Miami University
Oxford, OH 45056
Office: (513) 529-4206
Lab: (513) 529-4262
FAX: (513) 529-4243
http://www.cas.muohio.edu/botany/bot/henry.html
http://www.muohio.edu/ecology/
2003 Apr 07
2
Is it possible to have data stuctures like in C ?
I'am a very fresh R user and I'd like to know how I could create such
structures.
I saw R was objects-oriented but I can not find any doccumentation on
about how to build my hown ojects.
Thanks.
2003 Mar 14
2
numbers and decimal points
I have a question for our European readers: how common is it to use
commas as decimal points in spread-sheet and statistics applications?
Is it an inconvenience to require that all data use a period as decimal point?
(i.e., 3.14159 rather than 3,14159).
We're trying to make our program as foolproof as possible, and would
prefer not to give users a chance to have commas as both decimal
2003 Apr 14
5
removing NULL elements from a list
Dear All,
I have a list, where several components are NULL, and I'd like to obtain that
very same list without the NULL components (i.e., I do not want to unlist or
otherwise loose the rest of the list structure). I can do that with a loop,
but how could I do it without a loop?
Thanks,
Ram?n
--
Ram?n D?az-Uriarte
Bioinformatics Unit
Centro Nacional de Investigaciones Oncol?gicas (CNIO)
2003 Apr 10
2
New problem
Hi all, and thx a lot for your answers,
in fact i know that R deals with logical numbers 0 and 1 the same way like TRUE and FALSE but my problem is in fact with C language.
I have done an interface with C and my first problem was with float variables, but this warning doesn't appear everytime and really i don't know the problem with R:
"Warning message:
DLL attempted to change
2003 Apr 22
3
lexical scope
Hi everyone
another documented feature that was a bit unexpected for me:
R> x <- 19
R> f <- function(t){t+x}
R> f(100)
[1] 119
--as expected: x is visible from within f()
..but...
R> g <- function(a){x <- 1e99 ; return(f(a))}
R> g(4)
[1] 23
--the "x" that is visible from within g() is just 19, which is not the
one I expected it to find.
R> rm(x)
2006 Oct 18
2
Adding locfit confidence intervals in trelis xyplot
Dear all,
I am trying to include confidence intervals in a xyplot.
This is what I am doing:
xyplot(x ~ y|z, alpha = 1,band = "global",panel = panel.locfit)
(more specifically, in my case x is a binary response from a logistic
regression model)
The output plot was fine but it did not include the confidence intervals
Anyone knows how to do it? (xYplot did not work either)
many thanks