Re: [R] Using item difficulties from a fitted Partial Credit Model to predict person abilities in an extended dataset?

> > Bert Gunter > > "The trouble with having an open mind is that people keep coming along and > sticking things into it." > -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) > > > On Sun, Jun 7, 2020 at 3:59 AM Rob Forsyth >

[R] Using item difficulties from a fitted Partial Credit Model to predict person abilities in an extended dataset?

I am using the eRm package to examine the properties of a clinical rating scale using a Partial Credit Model (PCM). I understand how to extract the person ability estimates (thetas) from a simple fitted PCM but I have a dataset with repeated observations over time (~1200 observations of the inst

Re: [R] padding specific missing values with NA to allow cbind

-Original Message- >> From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On >> Behalf >> Of Rob Forsyth >> Sent: Monday, June 10, 2013 2:42 PM >> To: r-help@r-project.org >> Subject: [R] padding specific missing values with NA

[R] padding specific missing values with NA to allow cbind

Dear list Getting very frustrated with this simple-looking problem > m1 <- lm(x~y, data=mydata) > outliers <- abs(stdres(m1))>2 > plot(x~y, data=mydata) I would like to plot a simple x,y scatter plot with labels giving custom information displayed for the outliers only, i.e. I would like to def

[R] Problem with constrained nlsList model

I have some longitudinal data I'm fitting with an asymptotic growth function constrained to the origin. Visual inspection of the dataset suggests this is reasonable! > library(nlme) > results <- groupedData(y~Days | ID, data=results) > m1 <- nlsList(SSasympOrig, na.omit(results)) > m1 Call: Mo

[R] PCM() non-convergence problem: how to get diagnostics?

s trying to generate some diagnostics to get a better idea of what the problem(s) are, and/or adjust default parameters used in the nlm call to see if this helped achieve convergence. Setting options(warn=1) doesn't appear to help and am unclear how set flags such as print.level for the nlm c

[R] Accessing variable's name as an attribute?

Sorry - I suspect this is a very basic query. I have a data frame structured "flat" (i.e. separate observations for a given subject ID on separate lines). Using the nlme library I create a groupedData object suitable for further analysis thus: dataset <- groupedData(VARIABLE ~ TIME|ID, data=sfa

[R] Error handling in nlme call

no actual error message is reported during the run. Is there a way to test for this condition? Thanks Rob Forsyth __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-projec

[R] Accessing the fixed- and random-effects variance-covariance matrices of an nlme model

I would appreciate confirmation that the function vcov(model.nlme) gives the var-cov matrix of the fixed effects in an nlme model. Presumably the random-effects var-cov matrix is given by cov(ranef (model.nlme)? Rob Forsyth __ R-help@r-project.org

[R] Extracting variance-covariance matrix from nlme object

base stats package suitable? If so, why is the additional getVarCov provided? thank you Rob Forsyth __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting