You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
40 lines
852 B
R
40 lines
852 B
R
12 months ago
|
###################################################
|
||
|
# Function: generate_diff_irt
|
||
|
# Generates item difficulty threshold matrix for
|
||
|
# IRT model simulation
|
||
|
###################################################
|
||
|
|
||
|
|
||
|
generate_diff_irt <- function(J=7,M=4) {
|
||
|
# if J=7, item 5. Else, item 3
|
||
|
if(J==7){
|
||
|
i <- 5
|
||
|
}
|
||
|
if(J==4){
|
||
|
i <- 3
|
||
|
}
|
||
|
difficulties = matrix(c(0), J,M-1)
|
||
|
rownames(difficulties)=paste("item",1:J)
|
||
|
colnames(difficulties)=paste("Moda", 1:(M-1))
|
||
|
for (j in 1:J){
|
||
|
difficulties[j,1] = qnorm(j/(J+1))
|
||
|
}
|
||
|
for (j in 1:J){
|
||
|
for (m in 2:(M-1)){
|
||
|
difficulties[j,m]= difficulties[j,1]+(m-1)*2/(M-2)
|
||
|
}
|
||
|
}
|
||
|
difficulties = difficulties-mean(difficulties)
|
||
|
return(difficulties)
|
||
|
}
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
###################################################
|
||
|
# GENERATE MATRIX FOR SIMULATION
|
||
|
###################################################
|
||
|
|
||
|
|