[R] mirt-simdata question.

[Suna Paek]

Hi. I always thank you all of the R program worker and researchers.

I am using R for my thesis, and I have a question.

I am simulating multi-dimensional and categorical items (polytomous) with mirt-simdata.
However, I wish each items' categories are normal distribution. I checked a lot of information from the internet. Unfortunately, I couldn't find a good one.
It looks like before version, there is a 'simdata_normal' function, but not anymore.
Is there another way to simulate the normal distribution of the multi-dimensional item polytomous-responses?

Here is my code, I was working on.

#two dimensional categorical data simulation
Theta <- rmvnorm(10000, sigma = matrix(c(1, .5, .5, 1), 2)) #correlation of .5
summary(Theta)

set.seed(12345)
#slope matrix of 20 rows=items, a1=10 factor 1, a2=10 factor 2
aa <- matrix(c(rlnorm(20,.2,.3),rep(0,40),rlnorm(20,.2,.3)),40) #rlnorm-log normal distribution
dd<-matrix(rnorm((40*4),0,2.0), 40)
dd <- t(apply(dd, 1, sort, decreasing=TRUE)) #sort since intercepts are ordered
polytomous4 <- simdata(aa, dd, 10000, Theta=Theta, itemtype = 'gpcm')
summary(polytomous4)

Can anyone please check and help me?
I desperately have to figure out this problem as soon as possible.

Thank you very much for reading my question.
Have a good day.
God bless you!

Best,



Soonhwa(Suna) Paek
Educational Psychology-Statistics and Measurements
University of Wisconsin-Milwaukee
paek using uwm.edu 262-441-3019



Soonhwa(Suna) Paek
Educational Psychology-Statistics and Measurements
University of Wisconsin-Milwaukee
paek using uwm.edu 262-441-3019

________________________________
From: Suna Paek
Sent: Wednesday, July 10, 2019 3:46 PM
To: R-windows using R-project.org
Subject: mirt-simdata question.

Hi. I always thank you all of the R program worker and researchers.

I am using R for my thesis, and I have a question.

I am simulating multi-dimensional and categorical items (polytomous) with mirt-simdata.
However, I wish each items' categories are normal distribution. I checked a lot of information from the internet. Unfortunately, I couldn't find a good one.
It looks like before version, there is a 'simdata_normal' function, but not anymore.
Is there another way to simulate the normal distribution of the multi-dimensional item polytomous-responses?

Here is my code, I was working on.

#two dimensional categorical data simulation
Theta <- rmvnorm(10000, sigma = matrix(c(1, .5, .5, 1), 2)) #correlation of .5
summary(Theta)

set.seed(12345)
#slope matrix of 20 rows=items, a1=10 factor 1, a2=10 factor 2
aa <- matrix(c(rlnorm(20,.2,.3),rep(0,40),rlnorm(20,.2,.3)),40) #rlnorm-log normal distribution
dd<-matrix(rnorm((40*4),0,2.0), 40)
dd <- t(apply(dd, 1, sort, decreasing=TRUE)) #sort since intercepts are ordered
polytomous4 <- simdata(aa, dd, 10000, Theta=Theta, itemtype = 'gpcm')
summary(polytomous4)

Can anyone please check and help me?
I desperately have to figure out this problem as soon as possible.

Thank you very much for reading my question.
Have a good day.
God bless you!

Best,



Soonhwa(Suna) Paek
Educational Psychology-Statistics and Measurements
University of Wisconsin-Milwaukee
paek using uwm.edu 262-441-3019

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