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GGUM (version 0.5)

plotICC: Plot item characteristic curves (ICCs)

Description

plot.ICC plots the ICCs for the GUM and the GGUM.

Usage

plotICC(IP, Th, items = NULL, quiet = FALSE)

Value

The function returns the correlation between observed and expected item scores (missing values pairwise removed).

Arguments

IP

Object of class GGUM.

Th

Theta estimates from function Theta.EAP().

items

Vector indicating the items for which the ICCs are to be plotted. Default is all items.

quiet

Render all plots for items at once? Default is FALSE.

Author

Jorge N. Tendeiro, tendeiro@hiroshima-u.ac.jp

Details

This function plots the item characteristic curves (ICCs).

Examples

Run this code
if (FALSE) {
# For GUM:
# Generate data
#   (toy example: Too few items (due to computation time constraints) for 
#   accurate estimation of person parameters; larger number of items is 
#   required in practice):
gen1 <- GenData.GGUM(400, 5, 3, "GUM", seed = 139)
# Fit the GUM:
fit1 <- GUM(gen1$data, 3)
th1  <- Theta.EAP(fit1)
# Plot ICCs:
plotICC(fit1, th1, items = 1, quiet = TRUE)
}
if (FALSE) {
# For GGUM:
# Generate data:
set.seed(1); C <- sample(3:5, 10, replace = TRUE)
gen2 <- GenData.GGUM(2000, 10, C, "GGUM", seed = 156)
# Fit the GGUM:
fit2 <- GGUM(gen2$data, C)
th2  <- Theta.EAP(fit2)
# Plot ICCs:
plotICC(fit2, th2, items = 1, quiet = TRUE)
}

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