plotINFO: Plot Information For 'eRm' objects

Description

Calculates and plots the individual or summed item information by Samejima (1969)

Usage

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plotINFO(ermobject, type = "both", theta = seq(-6, 6, length.out = 1001L), ...)

Arguments

ermobject

An object of class 'eRm'.

type

A string denoting the type of information to be plotted. Currently supports "item", "test" and "both" (default).

theta

Supporting or sampling points on the latent trait.

...

Further arguments. xlab sets the label of the x axis. ylabI and ylabT control the labeling of the item or test information plot. mainI and mainT set the titles for item/test information plots. legpos defines the positioning of the legend, as in plotICC.

Author(s)

Thomas Rusch

References

Samejima, F. (1969) Estimation of latent ability using a response pattern of graded scores. Psychometric Monographs, 17.

See Also

The function to calculate the item or test information, item_info and test_info.

Examples

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res <- PCM(pcmdat)
plotINFO(res)

Questions? Problems? Suggestions? or email at ian@mutexlabs.com.

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