similar to: Question about Package 'sampleSection' for IRT model

Dear all members, I am Phd. candidate student at Chulalongkorn U., Thailand. I am interested in expectation maximization algorithm (EM) and multiple imputation (MI) for imputation missing values(missing at random(MAR) and missing not at random (MNAR)) in IRT (3-PL). So, I want to know about package in R or function of EM and MI for simulate this problem I am looking forward your answer.

Dear all, I generate data under IRT mdel. I conducted 1000 replications. When I run, some replication was not fit with my model. So, replications were fit model were less than 1000 replication. If I want its run until 1000 replicaions. How shouldI write functin. Thank you, Kamontip [[alternative HTML version deleted]]

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I'm completely stumped and seem to be going around for 2 days in the wrong circles. Here's what I have in 2 dataframes: > dim(params.data); head(params.data, n=2) [1] 284 6 item a1 a2 b1 b2 c 1 1 0.6671587 0.9588642 -3.5 -3.437961 0.2 2 2 1.1296298 1.4899307 -3.5 -4.146118 0.2 > dim(examinees.data); head(examinees.data, n=2) [1] 1600 3 examinee

Hello, my question is; for a specific item, how can I create a plot with both the empirical probability of correct response and the predicted probability as a function of the mean of the ability intervals (similar to a BILOG plot). Thank you -- View this message in context: http://r.789695.n4.nabble.com/IRT-ltm-function-plot-for-probabilities-tp2714881p2714881.html Sent from the R help mailing

Hello forum, I have developed an IRT model for a set of items on a large reference sample. I now want to use the IRT parameters that were estimated in the reference sample to score new individuals, one at a time. What R package(s) would allow me to do this? Also, several covariates were associated with item thresholds in the reference sample, so I was wondering if any programs can take

Hi Everybody, I have just been introduced to R and have used the ltm package for calibrating items under IRT. I have been able to get the item parameters using the fit function under different models. I am using the 2PL model. I have got the parameters for some 300 items from 15 different tests using the function fit. Now I need to automatically generate tests such that they have atleast a

Hi: I need to apply the IRT model from Ramsay (1991), He apply the Smoothing Kernel to multiple choice test. Is possible in R?. Thank you, Xavier G. Ordonez Doctoral Student Universidad Complutense de Madrid

I have been struggling with the same problem for the past few hours and am desperately in need of some help. The code I am running is as follows: ## opening a data set on the desktop setwd("C:/Users/haillie/Desktop") UN2010<- read.csv("UN2010.csv",header=TRUE) ##calling libraries library(reshape) library(car) ## these are the variables I want to recode colname <-

Hi all, Could anyone tell me if there is some package that fits any Item Response Model (further the ltm package)? Regards, Caio --------------------------------- [[alternative HTML version deleted]]

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

Hello R: i work on an IRT simulation research. I've written a code to generate a single dataset.As i will repeat simulating the data 100 times under every condition, how can i write the R code to make it run the single simulation code 100 times and save the generate results each time? Thanks so much~

Dear All, does anybody know of a package (working under Linux) for multilevel IRT modelling? I'd love to do this without having to go on WINSTEPS or the like.. thanks for the attention! Federico Andreis ----- Dr. Federico Andreis Universit? degli Studi di Milano-Bicocca, PhD Student MEB Department, Karolinska Institutet, Stockholm, Visiting PhD Student -- View this message in context:

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(

I have the following item response theory (IRT) likelihood that I want to maximize w.r.t. to theta (student ability). L(\theta) = \prod(p(x)) Where p(x) is the 3-parameter logistic model when items are scored dichotomously (x_{ij} = 0 or 1) and p(x) is Muraki's generalized partial credit model when items are scored polytomously (x_{ij} = 0 \ldots J). Now, I wrote the following two functions

The first version of the package plink has been uploaded to CRAN. plink is a package for conducting unidimensional IRT scaling and chain linking for multiple groups for single-format or mixed-format common items. The package supports eight IRT models and four calibration methods. Dichotomous Models: 1PL, 2PL, 3PL Polytomous Models: -Graded response model -Partial credit model -Generalized

The first version of the package plink has been uploaded to CRAN. plink is a package for conducting unidimensional IRT scaling and chain linking for multiple groups for single-format or mixed-format common items. The package supports eight IRT models and four calibration methods. Dichotomous Models: 1PL, 2PL, 3PL Polytomous Models: -Graded response model -Partial credit model -Generalized

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, 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]]