pairwise (version 0.6.1-0)

gif: Graphical Item Fit Plots

Description

plotting function for plotting empirical and model derived category probability curves.

Usage

gif(pers_obj, itemnumber = 1, ra = 4, integ = "raw", kat = "all", ...)

Value

a plot with category probabilities.

Arguments

pers_obj

an object of class "pers" as a result from function pers.

itemnumber

an integer, defining the number of the item to plot the respective categoy probability for. This is set to an arbitrary default value of itemnumber = 1 to avoid error messages when you forget to choose an item to plot the expected score curves for.

ra

an integer, defining the (logit) range for x-axis

integ

either an integer, defining the number of integration points along the (logit) range on the x-axis to integrate the empirical theta values, or the character expression "raw" (default) which will use the rawscore groups as integration points.

kat

either an integer, defining for which category the empirical category probabilities should be plotted over the model derived category probability curves, or the character expression "all" (default) which will plot the empirical category probabilities for all categories.

...

arguments passed to plot

Details

no details in the moment.

Examples

########
data(bfiN)
pers_obj <- pers(pair(bfiN))
#### plot empirical category probabilities
gif(pers_obj = pers_obj, itemnumber = 1 )
gif(pers_obj = pers_obj, itemnumber = 1 , integ=8) # integration over 8 points
gif(pers_obj = pers_obj, itemnumber = 1 , integ=8, kat=1) # only for category number 1