Ffuns_plot | R Documentation |
These plots indicate whether an appropriate minimum of the fitting criterion was found.
The value of index should be at the function minimum, the first derivative be close to
zero there, and the second derivative should be positive. If these conditions are not
met, it may be worthwhile to use function indexfun
initialized with an approximate
minimum value of score index index to re-estimate the value of index.
Ffuns_plot(evalarg, index, SfdList, chcemat, plotindex=1)
evalarg |
A vector containingg the sore index values to be evaluated. |
index |
The vector of of length |
SfdList |
The list vector of length |
chcemat |
The entire |
plotindex |
A subset of the integers |
The curves are displayed in three vertically organized panels along with values of index and the values and first two derivative values of the fit criterion. If more than one index value is used, a press of the Enter or Return key moves to the next index value.
A list vector is returned which is of the length of argument plotindex
. Each
member of the vector is a gg
or ggplot
object for the associated
plotindex value
. Each plot can be displayed using the print
command.
The plots of item power are produced as a side value even if no output object is
specified in the call to the function.
Juan Li and James Ramsay
Ramsay, J. O., Li J. and Wiberg, M. (2020) Full information optimal scoring. Journal of Educational and Behavioral Statistics, 45, 297-315.
Ramsay, J. O., Li J. and Wiberg, M. (2020) Better rating scale scores with information-based psychometrics. Psych, 2, 347-360.
index_fun
,
Ffun
,
DFfun
# Example 1. Display fit criterion values and derivatives for the
# short SweSAT multiple choice test with 24 items and 1000 examinees
chcemat <- Quant_13B_problem_dataList$chcemat
index <- Quant_13B_problem_parmList$index
SfdList <- Quant_13B_problem_parmList$SfdList
plotindex <- 1:3
indfine <- seq(0,100,len=101)
Ffuns_plot(indfine, index, SfdList, chcemat, plotindex)
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