| simMPRM {pcIRT} | R Documentation |
simulate data according to MPRM
Description
With this function data sets according to the multidimensional polytomous Rasch model (MPRM) are simulated
Usage
simMPRM(itempar, persons = 500, seed = NULL)
Arguments
itempar |
a matrix with item category parameters; each row represents a category and each column an item (see details) |
persons |
an integer representing the number of persons (observations) of the data set (see details) |
seed |
a seed for the random number generated can optionally be set |
Details
Data are generated with category values starting with 0. Thus the first row of the matrix containing the item parameters is matched to the category value 0 and so on. The last category is the reference category. Please note, that the item category parameters of the last category have to be 0 (due to parameter normalization)!
Person parameters are generated by a standard normal distribution.
Value
datmat |
simulated data set |
true_itempar |
the fixed item parameters according to the input |
true_perspar |
the fixed person parameters |
Author(s)
Christine Hohensinn
References
Fischer, G. H. (1974). Einfuehrung in die Theorie psychologischer Tests [Introduction to test theory]. Bern: Huber.
Rasch, G. (1961). On general laws and the meaning of measurement in psychology, Proceedings Fourth Berekely Symposium on Mathematical Statistiscs and Probability 5, 321-333.
See Also
Examples
#set item parameters
item_p <- rbind(matrix(c(-1.5,0.5,0.5,1,0.8,-0.3, 0.2,-1.2), ncol=4),0)
#number of persons
pn <- 500
#simulate data set
simdatM <- simMPRM(item_p, pn)