Re: [R] Ask alpha cronbach and Hoyt method

2007-09-03 Thread Doran, Harold
Hoyt's ANOVA and Cronbach's alpha are the same statistic. I think there is an example in Nunnally and Bernstein. I have no idea what a W statistic is. Can you explain that? -Original Message- From: [EMAIL PROTECTED] on behalf of thamrin hm Sent: Mon 9/3/2007 3:37 AM To: R-help@stat.math

Re: [R] Variance explained in mixed models

2007-08-31 Thread Doran, Harold
Ahh, the key to getting what you want is to ask the same question over and over again. This question is not about R and an answer can be found in all basic books on hierarchical linear models. > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Simon P

Re: [R] standardized cronbach's alpha?

2007-08-21 Thread Doran, Harold
You can get this using alpha() or alpha.Summary() in the MiscPsycho package. Stratified alpha coefficients are coming for the next release, BTW. -Original Message- From: [EMAIL PROTECTED] on behalf of Steve Powell Sent: Tue 8/21/2007 10:02 AM To: r-help@stat.math.ethz.ch Subject: [R] sta

Re: [R] Robust Standard Errors for lme object

2007-08-07 Thread Doran, Harold
> -Original Message- > From: Thomas Lumley [mailto:[EMAIL PROTECTED] > Sent: Tuesday, August 07, 2007 11:06 AM > To: Doran, Harold > Cc: Lucy Radford; r-help@stat.math.ethz.ch > Subject: Re: [R] Robust Standard Errors for lme object > > On Tue, 7 Aug 2

Re: [R] Robust Standard Errors for lme object

2007-08-07 Thread Doran, Harold
Lucy: Why are you interested in robust standard errors from lme? Typically, robust standard errors are sought when there is model misspecification due to ignoring some covariance among units with a group. But, a mixed model is designed to directly account for covariances among units within a grou

Re: [R] lme and aov

2007-08-03 Thread Doran, Harold
Gang: I think what Peter is asking for is for you to put some of your output in an email. If the values of the fixed effects are the same across models, but the F-tests are different, then there is a whole other thread we will point you to for an explanation. (I don't presume to speak for other pe

Re: [R] Saving an expression to a file

2007-08-03 Thread Doran, Harold
Maybe use the sink() function > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Yuchen Luo > Sent: Thursday, August 02, 2007 10:17 PM > To: r-help@stat.math.ethz.ch > Subject: [R] Saving an expression to a file > > Dear Friends. > I have a very long

Re: [R] Matrix Multiplication, Floating-Point, etc.

2007-07-30 Thread Doran, Harold
at.math.ethz.ch; Doran, Harold > Subject: Re: [R] Matrix Multiplication, Floating-Point, etc. > > Thank you for responding! > > I realize that floating point operations are often inexact, > and indeed, the difference between the two answers is within > the all.equal tolerance

Re: [R] Matrix Multiplication, Floating-Point, etc.

2007-07-30 Thread Doran, Harold
This is giving you exactly what you are asking for. The operator * does element by element multiplication. So, .48 + -.48 =0, right? Is there another mathematical possibility you were expecting? > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Tal

Re: [R] Classification

2007-07-18 Thread Doran, Harold
Michael Assume your data frame is called "data" and your variable is called "V1". Converting this to a factor is: data$V1 <- factor(data$V1) Creating the classes can be done using ifelse(). Something like data$class <- ifelse(data$V1 < .21, A, ifelse(data$V1 < .41, B, C)) Harold > -Orig

Re: [R] reinforce library to re-load

2007-07-03 Thread Doran, Harold
I think you want to use detach() > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Weiwei Shi > Sent: Tuesday, July 03, 2007 3:27 PM > To: r-help@stat.math.ethz.ch > Cc: [EMAIL PROTECTED] > Subject: [R] reinforce library to re-load > > Hi, > > I am

Re: [R] sequences

2007-07-03 Thread Doran, Harold
Just take advantage of R's vectorized calculations as x <- seq(1:600) .8^x Harold > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of livia > Sent: Tuesday, July 03, 2007 12:05 PM > To: r-help@stat.math.ethz.ch > Subject: [R] sequences > > > Hi, I

[R] Spectral Decomposition

2007-06-29 Thread Doran, Harold
All of my resources for numerical analysis show that the spectral decomposition is A = CBC' Where C are the eigenvectors and B is a diagonal matrix of eigen values. Now, using the eigen function in R # Original matrix aa <- matrix(c(1,-1,-1,1), ncol=2) ss <- eigen(aa) # This results yields bac

Re: [R] degrees of freedom in lme

2007-06-25 Thread Doran, Harold
/2007 3:32 PM To: Doran, Harold Cc: Jean-Baptiste Ferdy; r-help@stat.math.ethz.ch Subject: Re: [R] degrees of freedom in lme On Mon, 2007-06-25 at 13:15 -0400, Doran, Harold wrote: > This is such a common question that it has a an "FAQ-like" response from Doug > Bates. Google &

Re: [R] degrees of freedom in lme

2007-06-25 Thread Doran, Harold
This is such a common question that it has a an "FAQ-like" response from Doug Bates. Google "lmer p-values and all that" to find the response. > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of > Jean-Baptiste Ferdy > Sent: Monday, June 25, 2007 12:

Re: [R] sampling problem - new to R

2007-06-06 Thread Doran, Harold
I dealt with something like this recently. x <- data.frame(plot = gl(2,5), tree = rnorm(10)) y <- split(x, x$plot) ss <- numeric(2) for(i in 1:2){ ss[i] <- sample(row.names(y[[i]][1]), 1) } z <- x[ss,] People help out of the goodness of the hearts and not for publication recognition.

Re: [R] lme vs. SAS proc mixed. Point estimates and SEs are the same, DFs are different

2007-06-05 Thread Doran, Harold
In addition to Peter's comments, the following link summarizes the issue as well. This is a direct response to the SAS/lmer DF issue. https://stat.ethz.ch/pipermail/r-help/2006-May/094765.html Harold > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf

Re: [R] What is the maximum size of a matrix?

2007-06-02 Thread Doran, Harold
Thanks for the clarification, Marc. Also, I should correct my error below. I wrote excel's limit is 16^2. But, it is 2^16 -1 -Original Message- From: Marc Schwartz [mailto:[EMAIL PROTECTED] Sent: Fri 6/1/2007 6:23 PM To: Doran, Harold Cc: Guanrao Chen; r-help@stat.math.ethz.ch Su

Re: [R] What is the maximum size of a matrix?

2007-06-01 Thread Doran, Harold
There is no maximum size. This will be driven by (at least) two issues. First, how much memory you have on your own computer and second what data you have in each cell. For instance, an integer takes less memory than a floating point. Other spreadsheet programs like excel limit the number of rows

Re: [R] random effects in lmer

2007-06-01 Thread Doran, Harold
Rina p-values are not generated as a part of the lmer object returned. If you read the ranef help it will show you two things. First, how you can get a "caterpillar plot" and second how you can get the posterior variances of the random effects. Then, you can do your test to see if they are diff

[R] Vignette for MiscPsycho Package

2007-05-15 Thread Doran, Harold
By the end of the day I will have a vignette completed for MiscPsycho. This vignette lays out the mathematical details for the primary functions in the package and provides substantive examples on how to use these functions in a sample session. This vignette will ultimately end up being distribute

[R] [R-pkgs] MiscPsycho Package 1.0

2007-05-08 Thread Doran, Harold
I have just submitted MiscPsycho to CRAN. MiscPsycho contains functions for miscellaneous psychometrics that may be useful for applied psychometricians. MML estimation already exists in the ltm package. Hence, a jml option is provided for users who prefer this method. The jml function gives back ra

Re: [R] [SPAM] - Re: R package development in windows - Bayesian Filter detected spam

2007-05-04 Thread Doran, Harold
> The best, of course, would be to get rid of Perl altogether. In Python, it is possible to make standalone executables. Is it possible to also do this in Perl, then one could eliminate a perl install. Or, is it possible to use Python to accomplish what perl is currently doing? I may be getting

Re: [R] [SPAM] - Re: R package development in windows - Bayesian Filter detected spam

2007-05-04 Thread Doran, Harold
Hi Gabor: I tried the link below, but it seems to be broken. > -Original Message- > From: Gabor Grothendieck [mailto:[EMAIL PROTECTED] > Sent: Friday, May 04, 2007 10:05 AM > To: Doran, Harold > Cc: Duncan Murdoch; r-help@stat.math.ethz.ch > Subject: [SPAM] -

Re: [R] R package development in windows

2007-05-04 Thread Doran, Harold
ase, this may be too disheartening. Harold > -Original Message- > From: Duncan Murdoch [mailto:[EMAIL PROTECTED] > Sent: Thursday, May 03, 2007 3:51 PM > To: Doran, Harold > Cc: Gabor Grothendieck; r-help@stat.math.ethz.ch > Subject: [SPAM] - Re: [SPAM] - Re: [R] R packag

Re: [R] [SPAM] - Re: R package development in windows - Bayesian Filter detected spam

2007-05-03 Thread Doran, Harold
age- > From: Duncan Murdoch [mailto:[EMAIL PROTECTED] > Sent: Thursday, May 03, 2007 3:24 PM > To: Doran, Harold > Cc: Gabor Grothendieck; r-help@stat.math.ethz.ch > Subject: [SPAM] - Re: [R] R package development in windows - > Bayesian Filter detected spam > > On 5/3/2007

Re: [R] R package development in windows

2007-05-03 Thread Doran, Harold
othendieck [mailto:[EMAIL PROTECTED] > Sent: Thursday, May 03, 2007 2:50 PM > To: Doran, Harold > Cc: r-help@stat.math.ethz.ch > Subject: Re: [R] R package development in windows > > It can find sh.exe so you haven't installed Rtools. > > There are several HowTo&#

[R] R package development in windows

2007-05-03 Thread Doran, Harold
I'm attempting to build an R package for distribution and am working from the directions found at http://www.maths.bris.ac.uk/~maman/computerstuff/Rhelp/Rpackages.html#Wi n-Win I've read through Writing R Extensions and various other "helpful" web sites. I've installed all relevant software (perl,

Re: [R] reference in article

2007-05-02 Thread Doran, Harold
citation() > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Tomas Mikoviny > Sent: Wednesday, May 02, 2007 11:44 AM > To: r-help@stat.math.ethz.ch > Subject: [R] reference in article > > Hi all R positive, > > does anyone know how to refer R in a

[R] Protocol for data inclusion in new packages

2007-04-27 Thread Doran, Harold
In the near future I will release MiscPsycho, a package that contains various functions useful for applied psychometricians. I would like to include some data sets for distribution in the package, but have not created any of these on my own, but have used data distributed in other packages such as

Re: [R] creating random numbers

2007-04-25 Thread Doran, Harold
sample(1:2, 10, replace=TRUE) > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of raymond chiruka > Sent: Wednesday, April 25, 2007 9:45 AM > To: r-help@stat.math.ethz.ch > Subject: [R] creating random numbers > > l want to create a column of 1

Re: [R] convergence

2007-04-19 Thread Doran, Harold
No, use a while loop. Something like change <- 1 while(abs(change) > .001 ){ do stuff change <- updated change } > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of rach.s > Sent: Thursday, April 19, 2007 8:00 AM > To: r-help@stat.math.

Re: [R] Modelling Heteroscedastic Multilevel Models

2007-04-17 Thread Doran, Harold
I think there are many who can help, but this question is quite vague. This assumes we have access to the book you note and can make sense of your question w/o sample data. If you cannot find a sample data set please create a sample data file. However, there are so many sample data sets in the mlm

Re: [R] argmax

2007-04-04 Thread Doran, Harold
x <- c(1,4,15,6,7) which(x==max(x)) > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of > [EMAIL PROTECTED] > Sent: Wednesday, April 04, 2007 11:14 AM > To: r-help@stat.math.ethz.ch > Subject: [R] argmax > > Hello, > > Is there any function that re

Re: [R] Power analysis and mixed model

2007-04-04 Thread Doran, Harold
One option is to use lmer in a monte carlo simulation. I just did this last week. Check out the article published in the American Statistician and can be found at http://maven.smith.edu/~nhorton/R/r.pdf. The article is not about power per se, but is about R as a toolbox for mathematical statist

Re: [R] the numimum number of fixed factors lme package can dealwith

2007-04-04 Thread Doran, Harold
As Doug noted yesterday, you may have a limit on the memory needed to create the model matrix for the fixed effects. But, aside from that, based on what I see below, it appears you have manually created a model matrix yourself. If that's true, you don't need to do that. You can create a single colu

Re: [R] Gaussian Adaptive Quadrature

2007-03-21 Thread Doran, Harold
The function integrate() uses AGQ. There are other functions for gaussian quadrature in the statmod() package that I really like. > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Caio > Lucidius Naberezny Azevedo > Sent: Wednesday, March 21, 2007 5

[R] time demean model matrix

2007-03-09 Thread Doran, Harold
Suppose I have longitudinal data and want to use the econometric strategy of "de-meaning" a model matrix by time. For sake of illustration 'mat' is a model matrix for 3 individuals each with 3 observations where ``1'' denotes that individual i was in group j at time t or ``0'' otherwise. mat <

Re: [R] R in Industry

2007-02-08 Thread Doran, Harold
It's been an interseting game of "telephone". Actually, the thread started with a recommendation to have a place on CRAN for prospective employers to place job adverts that require R as a skill. I think the sig is a good idea. But, I think it would be much easier to have something akin to what Pyt

[R] R in Industry

2007-02-06 Thread Doran, Harold
The other day, CNN had a story on working at Google. Out of curiosity, I went to the Google employment web site (I'm not looking, but just curious). In perusing their job posts for statisticians, preference is given to those who use R and python. Other languages, S-Plus and something called SAS wer

Re: [R] Cronbach's alpha

2007-01-24 Thread Doran, Harold
Hi Dave We had a bit of an off list discussion on this. You're correct, it can be negative IF the covariance among individual items is negative AND if that covariance term is larger than the sum of the individual item variances. Both of these conditions would be needed to make alpha go negative.

Re: [R] Cronbach's alpha

2007-01-24 Thread Doran, Harold
Weiwei Something is wrong. Coefficient alpha is bounded between 0 and 1, so negative values are outside the parameter space for a reliability statistic. Recall that reliability is the ratio of "true score" variance to "total score variance". That is var(t)/ var(t) + var(e) If all variance is tru

Re: [R] Replace missing values in lapply

2007-01-24 Thread Doran, Harold
representation. I need to walk through this and see what turns up. Thanks for the recommendation. > -Original Message- > From: Gabor Grothendieck [mailto:[EMAIL PROTECTED] > Sent: Wednesday, January 24, 2007 11:06 AM > To: Doran, Harold > Cc: r-help@stat.math.ethz.ch &

Re: [R] Replace missing values in lapply

2007-01-24 Thread Doran, Harold
Perfect, thxs > -Original Message- > From: Dimitris Rizopoulos > [mailto:[EMAIL PROTECTED] > Sent: Wednesday, January 24, 2007 10:49 AM > To: Doran, Harold > Cc: r-help@stat.math.ethz.ch > Subject: Re: [R] Replace missing values in lapply > > you need

[R] Replace missing values in lapply

2007-01-24 Thread Doran, Harold
I have some matrices stored as elements in a list that I am working with. On example is provided below as TP[[18]] > TP[[18]] level2 level1 1 2 3 4 1 79 0 0 0 2 0 0 0 0 3 0 0 0 0 4 0 0 0 0 Now, using prop.table on this gives > prop.table(TP[[18]],1)

[R] Matrix operations in a list

2007-01-23 Thread Doran, Harold
I have matrices stored within a list like something as follows: a <- list(matrix(rnorm(50), ncol=5), matrix(rnorm(50), ncol=5)) b <- list(matrix(rnorm(50), nrow=5), matrix(rnorm(50), nrow=5)) I don't recall how to perform matrix multiplication on each list element such that the result is a new li

Re: [R] Help with problem - multilevel model?

2007-01-18 Thread Doran, Harold
Aov is not the right function for this problem. Lmer is designed for multilevel modeling. There are a lot of resources, but start with the following vignette Library(lme4) vignette("MlmRevSoft") And then turn to Pinhiero and Bates > -Original Message- > From: [EMAIL PROTECTED] > [mailto

Re: [R] changes in the structure of mer objects?

2007-01-15 Thread Doran, Harold
help(package='lme4') will tell you > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of > [EMAIL PROTECTED] > Sent: Monday, January 15, 2007 8:37 AM > To: Martin Maechler > Cc: [EMAIL PROTECTED]; r-help@stat.math.ethz.ch; > [EMAIL PROTECTED] > Subject

Re: [R] differential item function for item response theory

2007-01-09 Thread Doran, Harold
I don't know of any functions specifically designed to handle DIF (e.g., mantel-hantzel). But, ltm does give you the point estimates and standard errors so you can do a t-test between the focal and reference groups. > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECT

Re: [R] OT: any recommendation for scripting language

2006-12-31 Thread Doran, Harold
I'm a bit new with python, but have found it extremely easy to learn and use. I have been using it to pre-process some text files that we often deal with and need to be formatted in a certain way before they can be used for statistical analysis in another software program. I suppose there is one t

Re: [R] \Sexpr in MikTex

2006-12-21 Thread Doran, Harold
I don't run the program this way so I don't know. But it makes me wonder if the problem is with \Sexpr{} or the way she is trying to run Sweave and compile. So, is it possible that code chunks are working but not \Sexpr{}? If you have something like <<>>= R code here @ Do you get that output?

Re: [R] \Sexpr in MikTex

2006-12-20 Thread Doran, Harold
Suzette I have not experienced any problems with \Sexpr{} and new R versions. It might be helpful if you could provied a minimal example of your .Rnw and how \Sexpr{} is used within. It is obvious what OS you're using given the path dirctories below, but normally it might be useful to be expli

Re: [R] Obtaining Estimates of the Random Effects Parameters

2006-12-13 Thread Doran, Harold
?VarCorr > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Rick Bilonick > Sent: Wednesday, December 13, 2006 11:40 AM > To: R Help > Subject: [R] Obtaining Estimates of the Random Effects Parameters > > I'm running simulation using lme and sometime

Re: [R] help on determining operating system

2006-12-12 Thread Doran, Harold
BTW, Mac OS sits on the Darwin unix system. So, you have all the benefits of Mac and can access unix via the terminal (Steve Jobs is brilliant). Things like emacs are waiting for you to use on the Mac. I haven't explored whether one can install R on the Mac and use it via the unix interface (or whe

Re: [R] intercept value in lme

2006-12-06 Thread Doran, Harold
t: Wednesday, December 06, 2006 12:07 PM > To: Doran, Harold > Cc: r-help@stat.math.ethz.ch > Subject: Re: [R] intercept value in lme > > It is boundend, you're right. In fact it is -25<=X<=0 > > These are cross-national survey data (I was investigated 7 > countries

Re: [R] intercept value in lme

2006-12-06 Thread Doran, Harold
As Andrew noted, you need to provide more information. But, what I see is that your model assumes X is continuous but you say it is bounded, -25 < X < 0 > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of victor > Sent: Wednesday, December 06, 2006 3:3

[R] Comparing posterior and likelihood estimates for proportions (off topic)

2006-12-05 Thread Doran, Harold
This question is slightly off topic, but I'll use R to try and make it as relevant as possible. I'm working on a problem where I want to compare estimates from a posterior distribution with a uniform prior with those obtained from a frequentist approach. Under these conditions the estimates should

Re: [R] Aggregating data

2006-11-29 Thread Doran, Harold
David: Is this what you are looking for? set.seed(10) tmp <- data.frame(group = gl(3,10), something = rnorm(30)) with(tmp, tapply(something, group, mean)) 1 2 3 -0.4906568 0.3695915 -0.9129640 > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAI

Re: [R] Making a case for using R in Academia

2006-11-09 Thread Doran, Harold
I would turn this on its head. The problem with social science grad schools is that students are not expected to know R. In my org doing psychometrics, we won't even consider an applicant if they only know SPSS. > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] O

Re: [R] Numerical Integration

2006-11-08 Thread Doran, Harold
You might try the statmod package which provides nodes and weights for gaussian quadrature. > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Xiaofan Cao > Sent: Wednesday, November 08, 2006 12:43 PM > To: r-help@stat.math.ethz.ch > Subject: [R] Nume

Re: [R] correaltion equal 1

2006-11-03 Thread Doran, Harold
or, it could mean you need to recenter your time variable. -Original Message- From: [EMAIL PROTECTED] on behalf of Marc Bernard Sent: Fri 11/3/2006 7:24 AM To: r-help@stat.math.ethz.ch Subject: [R] correaltion equal 1 Dear All, I wonder if this is a technical or an interpretation

Re: [R] correlation argument for lmer?

2006-11-02 Thread Doran, Harold
Not currently. > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of John Fox > Sent: Thursday, November 02, 2006 9:51 AM > To: 'R-help' > Subject: [R] correlation argument for lmer? > > Dear r-help members, > > Can lmer() in the lme4 package fit model

Re: [R] extract values from a vector

2006-11-01 Thread Doran, Harold
You could do this > V1 <- c("apple","honey","milk","bread","butter") > V2 <- c("bread","milk") > intersect(V1,V2) [1] "milk" "bread" > setdiff(V1,V2) [1] "apple" "honey" "butter" > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Antje > Sent: Wed

[R] Put a normal curve on plot

2006-10-31 Thread Doran, Harold
I would like to be able to place a normal distribution surrounding the predicted values at various places on a plot. Below is some toy code that creates a scatterplot and plots a regression line through the data. library(MASS) mu <- c(0,1) Sigma <- matrix(c(1,.8,.8,1), ncol=2) set.seed(123) x <- m

[R] Translating lme code into lmer was: Mixed effect model in R

2006-10-20 Thread Doran, Harold
This question comes up periodically, probably enough to give it a proper thread and maybe point to this thread for reference (similar to the 'conservative anova' thread not too long ago). Moving from lme syntax, which is the function found in the nlme package, to lmer syntax (found in lme4) is not

Re: [R] Automatic File Reading

2006-10-18 Thread Doran, Harold
See ?read.table and the FAQs on importing data > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Lorenzo Isella > Sent: Wednesday, October 18, 2006 11:09 AM > To: r-help@stat.math.ethz.ch > Subject: [R] Automatic File Reading > > Dear All, > I am gi

Re: [R] import rda data in R

2006-10-12 Thread Doran, Harold
Because rda files are R objects. Use load, not read.table > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Rita Gottloiber > Sent: Thursday, October 12, 2006 10:36 AM > To: r-help@stat.math.ethz.ch; r-help@stat.math.ethz.ch > Subject: [R] import rda

Re: [R] how to get the variance-covariance matrix/information of alphaand beta after fitting a GLMs?

2006-10-12 Thread Doran, Harold
?vcov From: [EMAIL PROTECTED] on behalf of zhijie zhang Sent: Thu 10/12/2006 9:56 AM To: R-help@stat.math.ethz.ch Subject: [R] how to get the variance-covariance matrix/information of alphaand beta after fitting a GLMs? Dear friends, After fitting a generali

Re: [R] treatment effect at specific time point within mixedeffects model

2006-10-05 Thread Doran, Harold
Hi David: In looking at your original post it is a bit difficult to ascertain exactly what your null hypothesis was. That is, you want to assess whether there is a treatment effect at time 3, but compared to what. I think your second post clears this up. You should refer to pages 224- 225 of Pinhi

Re: [R] glm with nesting

2006-10-05 Thread Doran, Harold
It's not really possible to help without knowing what errors you received and maybe some reproducible code. I think I remember this, though. From what I recall, there was no distinction between box and chick, so you cannot estimate both variance components. > -Original Message- > From:

Re: [R] line plot through NA

2006-10-02 Thread Doran, Harold
Do you mean something like this: plot(approx(Day,V), type='l') > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of > [EMAIL PROTECTED] > Sent: Monday, October 02, 2006 10:32 AM > To: r-help@stat.math.ethz.ch > Subject: [R] line plot through NA > >

Re: [R] multilevel factor model in lmer

2006-10-02 Thread Doran, Harold
Dan: lmer cannot currently be used for the 2PL. As you note, it is straightforward to estimate the 1PL, but the a-parameters present a current challenge. Doug mentioned to me the other day he is doing some work on this, so I have copied him on this reply. Harold -Original Message- Fr

Re: [R] Beginner question: select cases

2006-09-25 Thread Doran, Harold
Peter, There is a much easier way to do this. First, you should consider organizing your data as follows: set.seed(1) # for replication only # Here is a sample dataframe tmp <- data.frame(city = gl(3,10, label = c("London", "Rome","Vienna" )), q1 = rnorm(30)) # Compute the means with(tmp, tappl

Re: [R] how to ignore "NA" or replace it by another value

2006-09-21 Thread Doran, Harold
It depends a bit on what function you are using. For example, set.seed(1) xx <- c(NA, rnorm(10)) > mean(xx) [1] NA > mean(xx, na.rm=TRUE) [1] 0.1322028 Is how you would use this to compute a mean. Harold > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Beh

[R] Exponentiate a matrix

2006-09-21 Thread Doran, Harold
Suppose I have a square matrix P P <- matrix(c(.3,.7, .7, .3), ncol=2) I know that > P * P Returns the element by element product, whereas > P%*%P Returns the matrix product. Now, P^2 also returns the element by element product. But, is there a slick way to write P %*% P %*% P Obviously,

Re: [R] levels of factor when subsetting the factor

2006-09-12 Thread Doran, Harold
Also, it is probably easier to use gl() than coerce your data into a factor fact <- gl(3, 3, label = c("A", "B", "C")) > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Liaw, Andy > Sent: Tuesday, September 12, 2006 11:32 AM > To: Afshartous, David;

Re: [R] levels of factor when subsetting the factor

2006-09-12 Thread Doran, Harold
Just add the following to your code new.fact = fact[1:6, drop=T] > new.fact [1] A A A B B B Levels: A B > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of > Afshartous, David > Sent: Tuesday, September 12, 2006 11:23 AM > To: r-help@stat.math.ethz.

Re: [R] rename cols

2006-09-12 Thread Doran, Harold
I don't know, this seems pretty simple and intuitive (to me) # Create a sample data set with 439 variables tmp <- data.frame(matrix(c(rnorm(4390)), ncol=439)) colnames(tmp)<-paste("col", 1:439, sep = "") # rename a certain variable in that dataset names(tmp)[(which(names(tmp)=='col1'))]<-'NewName

Re: [R] rename cols

2006-09-11 Thread Doran, Harold
names(data) <- c('Apple', 'Orange') > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Ethan Johnsons > Sent: Monday, September 11, 2006 12:49 PM > To: r-help@stat.math.ethz.ch > Subject: [R] rename cols > > A quick question please! > > How do you r

Re: [R] Create a vector from another vector

2006-08-30 Thread Doran, Harold
Hi Duncan Here is a bit more detail, this is a bit tough to explain, sorry for not being clear. Ordering is not important because the vector I am creating is used as a sufficient statistic in an optimization routine to get some MLEs. So, any combination of the vector that sums to X is OK. But, the

[R] Create a vector from another vector

2006-08-30 Thread Doran, Harold
Dear list Suppose I have the following vector: x <- c(3,4,2,5,6) Obviously, this sums to 20. Now, I want to have a second vector, call it x2, that sums to x where 5 <= x <= 20, but there are constraints. 1) The new vector must be same length as x 2) No element of the new vector can be 0 3) Ele

[R] Optim question

2006-08-24 Thread Doran, Harold
This is a very basic question, but I am a bit confused with optim. I want to get the MLEs using optim which could replace the newton-raphson code I have below which also gives the MLEs. The function takes as input a vector x denoting whether a respondent answered an item correctly (x=1) or not (x=0

Re: [R] Random structure of nested design in lme

2006-08-23 Thread Doran, Harold
Why are the results not reliable? From: ESCHEN Rene [mailto:[EMAIL PROTECTED] Sent: Wednesday, August 23, 2006 3:48 AM To: Spencer Graves; r-help@stat.math.ethz.ch Cc: Doran, Harold Subject: RE: [R] Random structure of

Re: [R] Variance Components in R

2006-08-17 Thread Doran, Harold
mailto:[EMAIL PROTECTED] On Behalf Of Iuri Gavronski Sent: Thursday, August 17, 2006 1:26 PM To: Doran, Harold Cc: r-help@stat.math.ethz.ch Subject: Re: [R] Variance Components in R I am trying to replicate Finn and Kayandé (1997) stud

Re: [R] Variance Components in R

2006-08-17 Thread Doran, Harold
This will give you many examples. vignette('MlmSoftRev') From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Iuri Gavronski Sent: Thursday, August 17, 2006 11:16 AM To: Doran, Harold Subject: Re: [R] Vari

Re: [R] Variance Components in R

2006-08-17 Thread Doran, Harold
Iuri: The lmer function is optimal for large data with crossed random effects. How large are your data? > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Iuri Gavronski > Sent: Thursday, August 17, 2006 11:08 AM > To: Spencer Graves > Cc: r-help@stat

Re: [R] read.csv issue

2006-08-16 Thread Doran, Harold
6 PM > To: Doran, Harold > Cc: r-help@stat.math.ethz.ch > Subject: Re: [R] read.csv issue > > On Wed, 16 Aug 2006, Prof Brian Ripley wrote: > > > Set allowEscapes = FALSE when reading. See the help page > for more details. > > > > There is perhaps an argum

Re: [R] read.csv issue

2006-08-16 Thread Doran, Harold
om: jim holtman [mailto:[EMAIL PROTECTED] Sent: Wednesday, August 16, 2006 3:10 PM To: Doran, Harold Cc: r-help@stat.math.ethz.ch Subject: Re: [R] read.csv issue Try 'gsub' > y schid

[R] read.csv issue

2006-08-16 Thread Doran, Harold
I'm trying to read in some data from a .csv format and have come across the following issue. Here is a simple example for replication # A sample .csv format schid,sch_name 331-802-7081,School One 464-551-7357,School Two 388-517-7627,School Three \& Four 388-517-4394,School Five Note the third lin

Re: [R] [SPAM] - RE: REML with random slopes and random intercepts giving strange results - Bayesian Filter detected spam

2006-08-16 Thread Doran, Harold
Can you provide the summary(m2) results? > -Original Message- > From: Simon Pickett [mailto:[EMAIL PROTECTED] > Sent: Wednesday, August 16, 2006 7:14 AM > To: Doran, Harold > Cc: r-help@stat.math.ethz.ch > Subject: [SPAM] - RE: [R] REML with random slopes and random &

Re: [R] REML with random slopes and random intercepts giving strange results

2006-08-15 Thread Doran, Harold
I don't this is because you are using REML. The BLUPs from a mixed model experience some shrinkage whereas the OLS estimates would not. > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Simon Pickett > Sent: Tuesday, August 15, 2006 11:34 AM > To: r

Re: [R] about MCMC pack again...

2006-08-11 Thread Doran, Harold
Let's maybe back up a bit on this. You said you are interested in learning about the application of the Gibbs sampler for IRT models. I don't think opening the C++ code would be the best approach for this. Let me recommend the following article Patz, R. J., and Junker, B. W. (1999). A straig

Re: [R] fitting a model with the nlme package

2006-08-03 Thread Doran, Harold
> (out <- lmer(p ~ f - 1 + (1|h/t) + (1|j), set)) Doug: It seems the nesting syntax is handled a bit differently. Is (1|h/t) equivalent to the old lme nesting syntax? > > __ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/lis

Re: [R] standardized residuals (random effects) using nlme and ranef

2006-07-31 Thread Doran, Harold
> To sum up, I can't figure out how MLWin calculates the > standardized residuals. But I understand that this is not a > question for the R list. > Nevertheless, it would help if someone could point me to some > arguments why not to use them and stick to the results > obtainable by ranef().

Re: [R] standardized random effects with ranef.lme()

2006-07-31 Thread Doran, Harold
;m not sure why the help says that the standardized random effects are divided by the corresponding SE. Maybe he can clarify if he has time. I hope that helps Harold > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Doran, Harold >

Re: [R] standardized random effects with ranef.lme()

2006-07-30 Thread Doran, Harold
> > Why do the results differ although the estimates (random > effects and > > thus their variances) are almost identical? I noticed that > lme() does > > not compute the standard errors of the variances of the > random effects > > - for several reasons, but if this is true, how does > ran

Re: [R] Question about data used to fit the mixed model

2006-07-30 Thread Doran, Harold
You can have one observation per subject with multiple subjects nested in a group. If you only have 1 observation per group, then there is no multilevel structure to your data. For example, 30 students in a classroom or 20 employees in an office division are appropriate data structures. On the

Re: [R] how to fit with "lme" function

2006-07-25 Thread Doran, Harold
Nantachai It seems as though you have created the model matrices from the matrix representation of the model. This is unecessary as lme will construct those for you from your data frame. The first thing I recommend you do is use lmer instead of lme. Second, you should look in the vignette in t

Re: [R] Citations relevant to lmer methods

2006-07-25 Thread Doran, Harold
I just sent this to you in a personal response, but for purposes of archives, the following is one reference: @book{mccu:sear:2002, author ={Charles E. McCulloch and Shayle Searle}, year={2002}, title ={Generalized, Linear, and

Re: [R] trim function in R

2006-07-24 Thread Doran, Harold
One option is substr() > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Wade Wall > Sent: Monday, July 24, 2006 9:42 AM > To: r-help@stat.math.ethz.ch > Subject: [R] trim function in R > > Hi all, > I am looking for a function in R to trim the last

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