tff {pairwise} | R Documentation |
plotting function for plotting the test information function (TIF).
tff( pair_obj, items = NULL, x = NULL, main = "Test Information Function", plot = TRUE, cat = FALSE, lwd = 2, col = 1, ... )
pair_obj |
an object of class |
items |
optional a vector (character or numeric) identifying the items (according their order in the data) to use for plotting the test information function. |
x |
The value(s) of the latent variable, at which the TIF will be evaluated. |
main |
see parameters for |
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 "data.frame" or a single numeric with values of the Test information function.
######## data(sim200x3) result <- pair(sim200x3) tff(pair_obj = result) # TIF plot tff(pair_obj = result, cat=TRUE) # TIF plot tff(pair_obj = result, items=c("V1","V3"), cat=TRUE) # TIF plot tff(pair_obj = result, x=0) # TIF at theta=0 tff(pair_obj = result, x=seq(0,4,.1)) # TIF for a given range of Thetas ##### examples with other data ... data(bfiN) result <- pair(bfiN) tff(pair_obj = result) tff(pair_obj = result, cat=TRUE) # TIF plot