psych (version 1.0-23)

VSS.simulate: create VSS like data

Description

Simulation is one of most useful techniques in statistics and psychometrics. Here we simulate a correlation matrix with a simple structure composed of a specified number of factors. Each item is assumed to have complexity one.

Usage

VSS.simulate(ncases=1000, nvariables=16, nfactors=4, meanloading=.5)

Arguments

ncases

number of simulated subjects

nvariables

Number of variables

nfactors

Number of factors to generate

meanloading

with a mean loading

Value

• a ncases x nvariables matrix

See Also

VSS, ICLUST

Examples

simulated <- VSS.simulate(1000,20,4,.6)
vss <- VSS(simulated,rotate="varimax")
VSS.plot(vss)
## The function is currently defined as
function(ncases=1000,nvariables=16,nfactors=4,meanloading=.5)    
#generates a simple structure factor matrix
                                #with nfactors

{                                                                   
weight=sqrt(1-meanloading*meanloading)    #loadings are path coefficients
theta=matrix(rnorm(ncases*nfactors),nrow=ncases,ncol=nvariables) 
#generates nfactor independent columns, repeated nvariable/nfactor times)
error=matrix(rnorm(ncases*nvariables),nrow=ncases,ncol=nvariables)
#errors for all variables
items=meanloading*theta+weight*error      
#observed score = factor score + error score
return(items)
  }