conquestr (version 0.9.96)

informationWrightMap2: informationWrightMap2

Description

Plots test information function, relative to ability density, and item locations (delta dots).

Usage

informationWrightMap2(
  myItems,
  myAbilities,
  minTheta = -6,
  maxTheta = 6,
  stepTheta = 0.1,
  scaleInfo = 1
)

Value

A ggplot2 object.

Arguments

myItems

A list of sets of item parameters.

myAbilities

A vector of person abilities.

minTheta

The smallest value of ability PDF to plot.

maxTheta

The largest value of ability PDF to plot.

stepTheta

The increment to iterate over the ability PDF. Defaults to 0.01.

scaleInfo

A scaling factor to apply to the plot of tesr information. Because ability distribution is a PDF with area one, and a test information function has area L, this can make the plot more interpretable. Defaults to 1.

Examples

myDetaDot <- data.frame(
  id = 1:10,
  itemid = paste0("item_", letters[1:10]),
  delta = runif(n = 10, min = -3, max = 2)
)
myTau<- data.frame(
  id = c(rep(1:2, each = 1), rep (3, 2)), 
  itemid = paste0("item_", c(rep(letters[1:2], each = 1), rep(letters[3], 2))),
  step = c(1, 1, 1, 2),
  tau = c(-1.2, -0.3, -0.2, -0.1)
)
myItemParams<- makeItemList(myDetaDot, myTau)
myAbil <- rnorm(1000, 0, 1)
myInfoPlot <- informationWrightMap2(myItems= myItemParams, myAbilities = myAbil)