| dirf {lazy.irtx} | R Documentation |
Calculation of Derivative of Item Response Function
dirf(param, theta = NULL, weight = NULL, zero = 1, smallP = 0, thmin = -4, thmax = 4, npoints = 21, DinP = 1, print = 1, debug = 0, plot = 0)
param |
Item Parameter Data Frame |
theta |
Discrete theta values |
weight |
Weight data frame |
zero |
= 0 to exclude the xzero-th category from output |
smallP |
Minimum value of probability |
thmin |
Minimum value of discrete thata value |
thmax |
Maximum value of discrete thata value |
npoints |
# of discrete points for theta |
DinP |
= 1 to include D=1.7 in logistic function |
print |
= 1 to print result |
debug |
= 1 to print intemediate result |
plot |
= 1 to plot result |
A list of
dICRF, dIRF, dTRF, fromP, toP=toP, vecv, minscore_i, maxscore_i,
minscore_t, maxscore_tt
where
dICRF npoints x sum(ncat)
dIRF npoints x nitems weighted by item category weight
dTRF npoints x 1 weighted by item category weight
and item weight
fromP, toP location of each item category in dICRF
vectorize category weights
minscore_i mimimum score of each item
maxscore_i maximum score of each item
minscore_t mimimum score of test
maxscore_t maximum score of test
dirf( paramS1, plot=1 )