pcIRT (version 0.1)

simCRSM: simulate data according to CRSM

Description

With this function data sets according to the Continous Rating Scale Model are simulated

Usage

simCRSM(itempar, distr, perspar, mid = 0.5, len = 1, seed=NULL)

Arguments

itempar

a numerical vector with item parameters

distr

a number setting the distribution parameter for the item set

perspar

a numerical vector with the person parameters

mid

the midpoint of the response scale (on which the data set is generated)

len

the length of the response scale (on which the data set is generated)

seed

a seed for the random number generated can optionally be set

Value

• datmat
  simulated data set
• true_itempar
  the fixed item parameters according to the input
• true_distrpar
  the fixed distribution parameter according to the input
• true_perspar
  the fixed person parameters according to the input

Details

The midpoint and the length of the response scale define the interval of the data set generated. The default of the function generates data according to a response scale between 0 and 1 - that is midpoint 0.5 and length 1.

References

Mueller, H. (1987). A Rasch model for continuous ratings. Psychometrika, 52, 165-181.

See Also

simMPRM

Examples

#set item parameters
item_p <- c(-1.5,-0.5,0.5,1)

#set distribution parameter for items
dis_p <- 5

#generate person parameters by a standard normal distribution
pp <- rnorm(50, 0,1)

#simulate data set
#this is only an illustrating example for simulating data!
#In practice, a sample size of n=50 will be too small for most application demands
simdatC <- simCRSM(item_p, dis_p, pp)