gendata_gIRT {lazy.girt} | R Documentation |

Generation of Simulated Item Response Data under gIRT Model

gendata_gIRT(Ntot, param, DinP = 1, Nmat = NULL, thetaphi = NULL, npoint = NULL, theta = NULL, npointth = 7, thmin = -3, thmax = 3, phi = NULL, npointph = 5, phmin = 0, phmax = 5, thd = NULL, thdist = "NORMAL", thmean = 0, thstd = 1, phd = NULL, phdist = "GBETA", paramab = c(1, 3), nomiss = 0, compress = 0, sort = 1, thetaname = NULL)

`Ntot` |
# of total observations to be generated
If Ntot == 1, one observation per each theta point
will be generated, |

`param` |
Item Parameter Data Frame |

`DinP` |
= 1 to include D=1.7 in logistic function |

`Nmat` |
npoints x nitems matrix consisting of # of trials, or NULL. This will be used only when Ntot=1 and compress=0. |

`theta` |
Discrete theta values |

`thmin` |
Minimum value of discrete thata value |

`thmax` |
Maximum value of discrete thata value |

`thd` |
theta distribution probability vector |

`thdist` |
= "NORMAL" or "UNIFORM" or "rnorm" or "runif" |

`thmean` |
mean of theta distribution |

`thstd` |
std of theta distribution |

`nomiss` |
= 1 to exclude those theta points with N = 0. |

`compress` |
= 1 to compress the data when Ntot = 1. |

`sort` |
= 1 to sort the result according to theta. |

`thetaname` |
= Name of the variable which will contain theta value or NULL. |

`npoints` |
# of discrete points for theta, or # of random variables |

A list of

U, N, npoints, theta, thd, Ntot, fromP, toP, type, ncat, thmean, thstd
, compress, sort

where

If compress = 0 and Ntot is large,

U is npoints x sum of ncat[j]

U[,fromP[j]:toP[j]] is npoints x ncat[j]

U[,fromP[j]:toP[j]][i,k] contains # of responses to

the k-th category (k=0,1,...,ncat[j]) at theta[i]

to which N[i]=round(Ntot*thd[i]) observations belong.

If compress = 1 and Ntot = 1,

U is npoints x nitems

U[i,j] contains the response to the j-th item at theta[i]

where 0 <= U[i,j] <= ncat[j]-1.

In this case, fromP and toP are not compressed.

(theta, thd, N) are npoints x 1

N[i] is the # of observations at theta[i]

set.seed(1701) # 30 binary items param=paramBr # one obs per random theta-phi resg <- gendata_gIRT( 1, param, thdist="NORMAL", phdist="GBETA", compress=1 , npoint=500, phmin=0, phmax=2, paramab=c(1,4) ) Uc1=as.data.frame( resg$U ) thetaphi_ORG1=resg$thetaphi set.seed(1701) param=paramBG # one obs per theta-phi grid resg <- gendata_gIRT( 1, param, thdist="NORMAL", phdist="GBETA", compress=1 , npointth=501, thmin=-4, thmax=4 , npointph=3, phmin=0, phmax=2 ) Uc2=as.data.frame( resg$U ) thetaphi_ORG2=resg$thetaphi

[Package *lazy.girt* version 0.1.3 Index]