Can anyone advise me on the assumptions of IRT?

When I showed my refined scale after running a CFA and EFA (11 items, 3 factors, 4, 4, 3) a statistician at UCL told me that I had too few items per factor to run IRT. Does anyone have any...

31 December 2019 2,903 3 View

Why can't I run an IRT if I have more than one latent variable? Is there a minimum number of variables on a construct needed to run an IRT?

Hi, I am developing a psychometric scale. I have three factors and I have been told by my supervisors that I won't be able to run an IRT because there is more than one latent variable....

02 March 2019 2,155 1 View

(Repost) Would anyone like to take part in my study?

07 August 2018 4,692 0 View

Can I interpret Q-sort results without participants subjective comments on the items or general feedback?

Hi there, I did not formally ask follow-up questions or record any additional comments to the q-grid that my participants created whilst I conducted a Q-sort. Does this mean that I cannot fully...

06 July 2018 3,408 3 View

What are the similarities and comparisons between Mplus and R?

03 April 2016 2,337 5 View

Hi, I am developing an Employment Scale for people with PD, do I have to run an EFA/CFA on non-clinical samples first?

I am struggling to find references for testing structural validity of a scale on non-clinical samples first, before running an EFA and CFA on people with personality disorders. I was told this is...

01 January 1970 1,001 2 View

How to classify strictly upper triangular matrices by similarity?

Let F be a field. Consider U, the set of n times n strictly upper triangular matrices in F. For X, Y in U, we call them similar if there exists some S, which is non-degenerate and upper...

01 March 2021 2,957 8 View

Is CD44 degraded in lysosome together with hyaluronan after CD44 mediated endocytosis of hyaluronic acid?

Also when RHAMM binds hyaluronic acid, they get internalized, will RHAMM also be degraded? Or both CD44 and RHAMM will be transferred back to the cell membrane? Asking for breast cancer cell line...

01 March 2021 8,169 2 View

Why is the sum of the elements in a row in a Q matrix equal to zero?

When explaining substitution models, the substitutions are expressed as Q matrix. Why is the sum of the elements in a row zero?

28 February 2021 3,864 3 View

Distribution of particles in metal matrix?

How would define the "good" and "poor" distribution of particles within the matrix. Is there a quantitative solution to assess the distribution of the particles, which then having denotation of...

28 February 2021 7,397 8 View

How to find a correlation between coordinates in a curvilinear coordinate system?

Hello. I have a skewed elliptical coordinate system (I use alternative elliptical coordinates). And I need to determine connections between coordinates in order to fetch a covariance matrix of...

28 February 2021 364 3 View

For modelling epoxy-based matrices (in composites), which model in ABAQUS is the most suitable, Concrete damaged plasticity or Drucker-Prager model?

I am working on developing a micromechanical FE model for predicting kink-band formation in UD composites. To model matrix plasticity, which model, out of Concrete Damaged Plasticity and...

28 February 2021 5,415 1 View

What are the methods used for CNT..?

Respected Professor's i hope you are doing well and happy. i need some information about carbon Nanotubes. before blending the CNT with the matrix the CNT has been introducing in some treatments....

24 February 2021 5,383 5 View

How can I generate random samples from Bingham distribution in R? How can I construct those symmetric matrices?

in the function rbingham(n,A) in R software how can I construct that A (symmetric) matrix?

24 February 2021 3,528 3 View

How does the injection volume impact LLOQ and ULOQ in regression analysis (LC-MSMS)?

Hello, I have run into an issue that has sparkled a debate at work: is the LLOQ/ULOQ impacted by injection volume under the following circumstances: 1) Same dilution factor of all samples 2)...

23 February 2021 9,159 3 View

Multinomial probabilities and confidence intervals - obtaining the CI of the reference category?

Hi, Some background to my question: I have fitted 1st order multinomial Markov models with covariates. Since all probabiilties (for each row of the transition matrix) sum to 1, I estimate only...

22 February 2021 2,541 4 View