iff {pairwise} | R Documentation |
plotting function for plotting the Item information function(IIF).
iff( pair_obj, itemnumber = 1, x = NULL, plot = TRUE, cat = FALSE, lwd = 2, col = 1, ... )
pair_obj |
an object of class |
itemnumber |
an integer, defining the number of the item to plot the respective item information function for. This is set to an arbitrary default value of |
x |
The value(s) of the latent variable, at which the IIF will be evaluated. |
plot |
a logical (default |
cat |
a logical (default |
lwd |
see parameters for |
col |
see parameters for |
... |
arguments passed to plot |
no details in the moment.
a plot, a matrix or a single numeric with values of the Item information function.
######## data(sim200x3) result <- pair(sim200x3) # IFF plot for Item No. 2 iff(pair_obj = result, itemnumber = 2 ) # IFF plot for Categories of Item No. 2 iff(pair_obj = result, itemnumber = 2 ,cat=TRUE) # IFF at theta=0 for Item No. 2 iff(pair_obj = result, itemnumber = 2 ,x=0) # IFF at theta=0 for Categories of Item No. 2 iff(pair_obj = result, itemnumber = 2 ,x=0,cat=TRUE) # IFF of Item No. 2 for a given range of thetas iff(pair_obj = result, itemnumber = 2 ,x=seq(0,4,.1)) # ... etc. iff(pair_obj = result, itemnumber = 2 ,x=seq(0,4,.1),cat=TRUE) ##### examples with other data ... data(bfiN) result <- pair(bfiN) iff(pair_obj = result, itemnumber = 3 ) iff(pair_obj = result, itemnumber = 3 ,cat=TRUE)