similar to: IRT Package

> -----Original Message----- > From: r-help-bounces at stat.math.ethz.ch > [mailto:r-help-bounces at stat.math.ethz.ch]On Behalf Of Caio Lucidius > Naberezny Azevedo > Sent: 01 September 2005 12:09 > To: Help mailing list - R > Subject: [R] Multivariate Skew Normal distribution > > > Hi all, > > Could anyone tell me if there is any package (or function)

Dear R-users, I would like to know what are the commands to install (from a local zip file) a package and then to load it. Thaks all, Bests, Caio "Perco a consciencia, mas n併o importa, encontro a maior serenidade na alucina佺ao. 伾 curioso como n併o sei dizer quem sou. Quer dizer, sei-o bem, mas n併o posso dizer. Sobretudo tenho medo de dizer, porque no momento em que tento falar, n併o

Hi all, Does anybody know any function that performs gaussian adapative quadrature integration of univariate functions? Thanks in advance, Regards, Caio __________________________________________________ [[alternative HTML version deleted]]

Hi all, I need to solve double integrals with no closed solution. Calling x and y the two variables we have x ~ Normal(y*v,1) and y ~Half-Normal(0,1). In fact, given a joint funcion g(x,y), I need evaluate the integral of this function under that random structure. Could anyone suggest me a package or even a suitable method to solve this problem? Thanks all, Caio

Dear R-users, Does anybody know how to construct a block-diagonal matrix (with the blocks being different matrixs, concerning the dimension and the values) ? I would like to know also if there is any package that generates values from a multivariate skew normal distribution. Thanks all, Caio --------------------------------- [[alternative HTML version deleted]]

Dear R-users, Does anybody know how to construct a block-diagonal matrix (with the blocks being different matrixs, concerning the dimension and the values), without use loops ? Thanks all, Caio --------------------------------- [[alternative HTML version deleted]]

Hi all, I've been trying to install the "mvtnorm" package (in a Linux R version) without sucess. I write install.packages("mvtnorm",lib="/home/posmae/cnaber",repos="http://cran.uk.r-project.org/") and the following message arises ================================================== downloaded 160Kb * Installing *source* package 'mvtnorm'

Hello All, I was wondering how I can get the overall Pearson chi^2 test of model fit with its df and p value in the LTM package for the 2PL models. Thanks, -- Davood Tofighi Department of Psychology Arizona State University [[alternative HTML version deleted]]

Using the grm function (graded response IRT model) in the ltm package I receive the following error: Error: subscript out of bounds for several scales I'd like to examine. Here's a small example that if run a few times will likley produce the error at least once ch<-array(round(runif(50,1,5)),c(10,5)) grm(ch,start.val="random") ## or

Hi my friends, I have an issue with ability estimates when running GRM of IRT. I have responses from 242 subjects but got 183 ability estimates. Below is what I did to get the estimates. 1) I have a csv file "P1.csv" and I imported it into R and loaded the "ltm" package by doing: p1<-read.table("P1.csv",header=TRUE,sep=",") library(ltm) 2) I

hello R: we have a two-parameter IRT simulation code. The goal is to generate a response matrix.But the "for" part doesn't run. we don't know what is wrong with it. Thanks so much~~~ I <- 10 J <- 5 response <- matrix(0, 10, 5) pij <- function(a,b,theta) { a <- rnorm(J, 0.8, 0.04) a b <- rnorm(J, 0, 1) b theta <- rnorm(I, 0,1) theta for( i in 1:I ) { for(

Afternoon R help, I want to run Rasch/IRT analyses using the ltm package, however, I am using large scale survey data which requires weighting for accurate results. I attempted to create a weighted object to insert into the formulae of the ltm packages, however, the survey data only includes 30 replicate weights and a sampling weight. The svrepdesign requires additional information such as

Dear all, I'm working on ability estimates using Rasch model. Using the "ltm" package, the procedure is quite simple: ## Factor Scores for the Rasch model fit <- rasch(LSAT) factor.scores(fit) What about Partial Credit Model (PCM)? For PCM I use PCM function from eRm package. Is there any similar function like factor.scores to estimate ability scores using PCM model? Best,

The function factor.scores is used with package ltm and others to estimate IRT type scores for various models. It inherits objects of class grm, gpcm and a few others. What I would like to do is to use the factor.scores function, but feed it my own item parameters (from a bifactor model where the 2PL parameters are adjusted for the bifactor structure). Does anybody have an idea of how this might

Hello R, I am looking for non-parametric simulation in IRT. Is there any IRT package that does non-parametric simulation? helen L [[alternative HTML version deleted]]

Hai, Can anyone help me with some literature (R related) about latent models? Thanx, Wilfred

hello R, This is about simulation in psychomtrics in IRT in R. I want to simulate b parameters(item difficulty) with moments of fixed values of mean, st.d, skewness and kurtosis. Is there any specific IRT package in R with those functions to control those moments? I have seen other programs that can control mean and st.d but not skewness and kurtosis. Thank you, helen L [[alternative HTML

Hi my friends, I'm very new to R and need your help. I used R and ltm package for item response theory (IRT) modeling. I also need to compute differential item function (DIF) for IRT models. I searched the archive but basically found nothing. Could you help me find some sources about handling DIF of IRT? Many thanks in advance! Feng

I am using 32 bit R - 2.15.2 version and working on package ltm. The program does not give me any warning message when I run tpm command for a dataset. If run tpm command for the same dataset in 64-bit R 2.15.1 version, I get the warning message shown below. Can someone suggest why is no warning message being generated by 32-bit R? Or is it being generated but not getting printed? Which function

Hello All, I'm trying to print specific row and column for Observed_Scores matrix, however, when I execute the command "Observed_Scores[1,1]", I get the message "Error in Observed_Scores[1, 1] : incorrect number of dimensions". Could you please help and let me know where is the mistake? Here is my program: library(ltm) library(psych) # Settting the working directory