xxIRT (version 2.0.1)

irt_rescale_3pl: Rescale 3PL parameters

Description

Rescale parameters in a 3PL model

Usage

irt_rescale_3pl(x, parameter = c("theta", "b"), mean = 0, sd = 1)

Arguments

x

an IRT model object

parameter

the rescaling parameter

mean

the mean of the new scale

sd

the standard deviation of the new scale

Examples

# NOT RUN {
# rescale theta
x <- irt_model("3pl")$gendata(20, 5)
c(mean(x$people$theta), sd(x$people$theta))
y <- irt_rescale_3pl(x, "theta", 0, 1)
c(mean(y$people$theta), sd(y$people$theta))
round(abs(irt_stats(x, "prob") - irt_stats(y, "prob")), 2)
# rescale b
x <- irt_model("3pl")$gendata(20, 5)
c(mean(x$items$b), sd(x$items$b))
y <- irt_rescale_3pl(x, "b", 0, 1)
c(mean(y$items$b), sd(y$items$b))
round(abs(irt_stats(x, "prob") - irt_stats(y, "prob")), 2)
# }