search for: psychometrics

Dear R-Listers, to measure the psychometric curve of pitch discrimination, one sequentially presents two tones of slightly different pitch to an observer (animal will do), and asks "which is higher". The pschometric curve is the fraction of correct responses plotted against the pitch difference. It passes through 50% (pure guessing) at zero and normally approaches 100% at large

Hi, I want to fit some psychophysical data with cumulative gaussians. There is quite a convenient toolbox for matlab called 'psignifit' (formerly known as 'psychofit'). It allows the lower bound of the sigmoid to vary slightly from zero, aswell as the upper bound to vary from one. with these two free parameters, the fitted function is less sensitive to noisy data and outliers.

...s and are internally documented. But "eventually" can take a pretty long time. Also, I expect that some of this will wind up on www.jstatsoft.org, but again, probably not any time soon. Also, I would be more than willing to embed this stuff in general multi-person projects such as R in Psychometrics R in Econometrics R in Social Statistics but that will require someone else running these shows. For the time being, if you want to receive information about updates of this and related R code and papers in the area of multidimensional scaling, item response theory, choice models, factor anal...

Version 1.5 of the MiscPsycho package had been uploaded to CRAN (should hit mirrors in a day or so). This package has a set of functions that may be useful for psychometric applications. The package has been updated to include the following: 1) All functions (where appropriate) now use standard formula arguments 2) All functions now use S3 print and summary methods 3) Help files have been

Hi, What package would you recommend for analyzing the validity/reliability of multiple choice tests. Doing things such as classical test analysis, factor analysis, item response theory. I've used psychometric (item.exam), MiscPsycho (alpha.Summary), and ltm (rcor.test). MiscPsycho reported the numbers most similar to what I get in SPSS: corrected point biserial correlations,

Dear R-Experts, I was wondering how to fit a cumulative gaussian to a set of empirical data using R. On the R website as well as in the mail archives, I found a lot of help on how to fit a normal density function to empirical data, but unfortunately no advice on how to obtain reasonable estimates of m and sd for a gaussian ogive function. Specifically, I have data from a psychometric function

Dear list, has anyone written a package/function in R for computing a point- biserial resp. biserial correlation? Thanks in advance Bernd

Please can someone advise me how I can adjust correlations using bonferroni's correction? I am doing manny correlation tests as part of an investigation of the validity/reliability of a psychometric measure. Help would be so appreciated! Cheers, Louise

Dear R-Community, I'm currently trying to find a way to conduct a meta-analysis in R. I would like to analyze data from mostly-cross-sectional survey-studies. The effect sizes would be correlations. The R packages "meta" and "rmeta" are, as far as I can see, set up for analysis with effect sizes for differences (i.e. comparison of the means/odds-ratios of experimental

...d do a correct translation. There must be some more modern ones around, but where? I need the algorithms for a program I have written for exploring structural balance in sociometric group structures. Tom +----------------------------------------------------------------+ | Tom Backer Johnsen, Psychometrics Unit, Faculty of Psychology | | University of Bergen, Christies gt. 12, N-5015 Bergen, NORWAY | | Tel : +47-5558-9185 Fax : +47-5558-9879 | | Email : backer at psych.uib.no URL : http://www.galton.uib.no/ | +---------------------------------------------------------------...

Dear all, Is anybody knows simple method for creation norm tables for psychological tests for several groups distinguished by sex and age? best regards, Krzysztof

Dear users, In my psychometric test i have applied logistic regression on my data. My data consists of 50 predictors (22 continuous and 28 categorical) plus a binary response. Using glm(), stepAIC() i didn't get satisfactory result as misclassification rate is too high. I think categorical variables are responsible for this debacle. Some of them have more than 6 level (one has 10 level).

...r of installers which make it easy for a programmer to put together all the files needed and place them in the right place. And simeone should get the OpenSuse people to include R in the installation. Tom +----------------------------------------------------------------+ | Tom Backer Johnsen, Psychometrics Unit, Faculty of Psychology | | University of Bergen, Christies gt. 12, N-5015 Bergen, NORWAY | | Tel : +47-5558-9185 Fax : +47-5558-9879 | | Email : backer at psych.uib.no URL : http://www.galton.uib.no/ | +---------------------------------------------------------------...

Dear list: I'm hoping to tap in to the statistical expertise in the group, especially those familiar with simulation techniques. I'm finalizing a study where I obtain standard errors from two sources. The first source is a monte carlo simulation and the other source is an analytical model I have developed that appears to recover the standard errors from the simulation. All analysis are

Hello, I'm new to R and work with psychometrics (Item response theory). I was using a package called "cirt" to model a data that contains only 0s, 1s and 9s. The package is basically used for Monte Carlo Markov Chain estimation of parameters and I specified 5000 iterations. The model seems to run fine but when I try to recover odds rat...

Hi Everyone, I've got a question about data representation. I have some psychometric data with 5 scores for 15 different groups. I've been asked to show some kind of mean plots. The data below is the mean and SD for a given group, unfortunately my employer doesn't want me posting full datasets. :( The groups V,W,X,Y,Z are divided into Bottom, (B), Middle (M) and Top (T). An

...nts are separated by blanks, and that is not optimal for the creation of a table (in the word processing sense). Is there an option to generate tab-separated output in R ? That would solve the problem. Tom +----------------------------------------------------------------+ | Tom Backer Johnsen, Psychometrics Unit, Faculty of Psychology | | University of Bergen, Christies gt. 12, N-5015 Bergen, NORWAY | | Tel : +47-5558-9185 Fax : +47-5558-9879 | | Email : backer at psych.uib.no URL : http://www.galton.uib.no/ | +---------------------------------------------------------------...

Dear Professor Revelle and R-helpers, This is a two-part question: the first part is general, and the second is specific to the psych package. First question: In the past I've constructed composite variables from questionnaire data by using rowMeans(), and then correlating items with the scale using cor() as an informal check for "bad" items. Over the weekend I decided to take a

...eason that there are several nice packages containing useful stuff for SNA (Social Network Analysis). Information about packages, web sites, experienced persons in the field, etc. would be very welcome. Tom +----------------------------------------------------------------+ | Tom Backer Johnsen, Psychometrics Unit, Faculty of Psychology | | University of Bergen, Christies gt. 12, N-5015 Bergen, NORWAY | | Tel : +47-5558-9185 Fax : +47-5558-9879 | | Email : backer at psych.uib.no URL : http://www.galton.uib.no/ | +---------------------------------------------------------------...

Me and some colleagues are planning to write a textbook together ("Statistics using R") where the target audience for the book is psychologists and students of psychology. We thought that it might be a good idea to use a Wiki when writing the text. Is that a good idea? Does anybody have any experience in that direction? What alternatives are there? The tool (Wiki) would have to be