irtstudy | R Documentation |
Functions for estimating item response theory item and person parameters.
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)
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 |
... |
further arguments passed to or from other functions, including
|
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. |
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)
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