irtstudy: Item Response Theory Study

Description Usage Arguments Examples

Description

Functions for estimating item response theory item and person parameters.

Usage

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irtstudy(x, model = 1, complete = FALSE, ...)

rirf(ip, theta = seq(-4, 4, length = 100))

riif(ip, theta = seq(-4, 4, length = 100))

rief(ip, theta = seq(-4, 4, length = 100))

rtrf(ip, theta = seq(-4, 4, length = 100))

rtif(ip, theta = seq(-4, 4, length = 100))

rtef(ip, theta = seq(-4, 4, length = 100))

irtsim(ip, theta)

Arguments

x

matrix or data.frame of scored item responses, one row per person, one column per item.

model

integer for the number of paramters to estimate per item. The default of 1 specifies item intercepts or difficulties via the Rasch model, 2 additionally specifies item slopes or discriminations, and 3 additionally specifies varying lower asymptotes.

complete

logical with default FALSE indicating whether or not x should be reduced to rows with complete data across all columns.

...

further arguments passed to or from other functions, including glmer

ip

vector or matrix of item parameters, with a in the first column, b in the second, and c in the third.

theta

vector of thetas over which to estimate the corresponding function.

Examples

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ritems <- c("r414q02", "r414q11", "r414q06", "r414q09",
  "r452q03", "r452q04", "r452q06", "r452q07", "r458q01",
  "r458q07", "r458q04")
rsitems <- paste0(ritems, "s")
pisagbr <- PISA09[PISA09$cnt == "GBR", rsitems]
irtgbr <- irtstudy(pisagbr)

talbano/epmr documentation built on May 31, 2019, 2:51 a.m.