View source: R/generateHelpers.R
simplef | R Documentation |
returns expected score at a given value of theta.
simplef(theta, item, model, D)
theta |
a scalar value of theta. |
item |
an item design matrix that is of size response categories (k) by three. The three columns are:
|
model |
a string, either "muraki" or "conquest" (default) (see 10.1177/0146621697211001). This tells downstream functions what parameterisation has been used for the model and helps with plotting and other outputs. |
D |
a number, giving the scaling constant. Default is 1 (logistic metric). Other common values are D = 1.7 (to give the normal ogive metric) |
a double - the expected score at theta.
myTheta <- 0
myDelta <- 1.5
k <- 3
a <- 1
itemParamX <- seq(0, k-1, 1)
itemParamD <- rep(myDelta, k)
itemParamT <- c(0, -0.5, 0.5)
itemParamA <- rep(a, k)
itemParam <- cbind(itemParamX, itemParamD, itemParamT, itemParamA)
colnames(itemParam)<- c("x", "d", "t", "a")
myExpect <- simplef(myTheta, itemParam)
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.