Optimal calibration design for all items

Create a plot with optimal design for each item. Optimal design is represented by different colored lines for each item.

drawdesign_allitems(yyy, linew = NULL, ablim = 4, colvec = NULL)

Arguments

yyy

an optical object; the output of a call optical().

linew

linewidth for design.

ablim

ability limits; plots will be made in the range [-ablim, ablim].

colvec

vector of color sequence for items (default is the R-default black, red, green, etc.).

Value

An optimal design plot is displayed for all items.

Examples

# Example No.1
# 2PL-model for three items with parameters (a, b) equal to (1.6, -2), (1.6, 0.5),
# and (1.6, 2) for the first, second, and third items, respectively.

ip <- cbind(c(1.6, 1.6, 1.6), c(-2, 0.5, 2))
yyy <- optical(ip)
drawdesign_allitems(yyy)



if (FALSE) {
# Example No.2
# 2PL-models for six items; the parameters for these items are a=(1.62, 1.4, 0.98, 0.66, 0.92, 0.9),
# and b=(-0.47, -1.71, 0.62, -0.15, -1.71, 1.6), respectively.

ip <- cbind(c(1.62, 1.4, 0.98, 0.66, 0.92, 0.9), c(-0.47, -1.71, 0.62, -0.15, -1.71, 1.6))
bid <- c(1, 1, 1, 2, 2, 2)
yyy <- optical(ip, bid = bid, show_progress = 2)
drawdesign_allitems(yyy)

# Items of the same color that are in the same block.
drawdesign_allitems(yyy, colvec = bid)
}