Ffun {TestGardener}

Compute the negative log likelihoods associated with a vector of score index values.

Description

Ffun computes the negative log likelihoods for a set of examinees, each at a single value index.

Usage

  Ffun(index, SfdList, chcemat)

Arguments

index

A vector of size N containing values for score indices in the interval [0,100].

SfdList

A numbered list object produced by a TestGardener analysis of a test. Its length is equal to the number of items in the test or questions in the scale. Each member of SfdList is a named list containing information computed during the analysis.

chcemat

An N by n matrix of responses or, for a single examinee, a vector of length n.

Value

A vector of length N of negative log likelihood values.

Author(s)

Juan Li and James Ramsay

References

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.

See Also

make_dataList, index_fun, Ffun, Ffuns_plot

Examples

  #  Example 1:  Compute the values of the objective function for locating each  
  #  examinee or respondent for the 24-item short form of the SweSAT quantitative  
  #  test on the percentile score index continuum [0,100].
  #  Use only the first five examinees
  chcemat <- Quant_13B_problem_dataList$chcemat
  SfdList <- Quant_13B_problem_parmList$SfdList
  index   <- Quant_13B_problem_parmList$index
  Fval    <- Ffun(index[1:5], SfdList, chcemat[1:5,])