itemInfoOverTheta function

itemInfoOverTheta

Calculates item information over a rage of theta given a set of item parameters. Returns a data frame with item information at a discrete set of values of theta. This is useful for plotting item information functions.

Note this function is redundant - use testInfoOverTheta and pass a single item as a list.

itemInfoOverTheta(myItem, minTheta = -6, maxTheta = 6, stepTheta = 0.1)

Arguments

• myItem: A matrix of item parameters of the structure used in simplef
• minTheta: The smallest value of ability PDF to calculate info and to plot. Defaults to -6.
• maxTheta: The largest value of ability PDF to calculate info and to plot. Defaults to 6.
• stepTheta: The increment to iterate over the ability PDF. Defaults to 0.01.

Examples

anItem <- matrix(c(0,0,0,1,1,1,0,1), nrow = 2, byrow = TRUE)
itemInfoOverTheta(anItem)