cacIRT (version 1.0)

iif: Item information function

Description

Modified from irtoys

Usage

iif(ip, x)

Arguments

ip

x

Value

Examples

##---- Should be DIRECTLY executable !! ----
##-- ==>  Define data, use random,
##--	or do  help(data=index)  for the standard data sets.

## The function is currently defined as
function (ip, x) 
	{
	    if (is.null(dim(ip))) 
	        dim(ip) = c(1, 3)
        p3 = irf(ip, x)$f
        q3 = 1 - p3
        
        f<-matrix(NA,nrow = length(x),ncol = dim(ip)[1])
        
        for(i in 1:length(x)){ for(j in 1:dim(ip)[1]){
        		
        f[i,j] = (1.7*ip[j, 1])^2*q3[i,j]/p3[i,j]*((p3[i,j]-ip[j,3])^2/(1-ip[j,3]^2))  }}
       
	    r = list(x = x, f = f)
	    return(r)
	}