q_identified: Quantile function for true or observed scores for identified...

In mcbeem/giftedCalcs: Psychometrics for Gifted Program Identification

Quantile function for true or observed scores for identified students

Description

This is the conditional quantile function for identified students. Given a percentile, it returns the corresponding score (on a z-score metric).

Usage

q_identified(percentile, relyt, test.cutoff, valid, nom.cutoff, mu=0)

Arguments

percentile	The percentile of the distribution of identified students. Range (0, 1). Must not be exactly 0 or 1.
relyt	Confirmatory test reliability coefficient. Range (0, 1]. Must not be exactly 0. Defaults to 1; in this case, the returned value is an observed score. If an alternative value is supplied for relyt, the returned value is a true score.
test.cutoff	Confirmatory test cutoff percentile. Range (0, 1). Must not be exactly 0 or 1.
valid	Nomination validity coefficient. Controls the relatedness of the nomination scores and the confirmatory test scores. Range (0, 1). Must not be exactly 0 or 1, and must be less than the square root of the test reliability. Defaults to 1e-7 for a single- stage identification system.
nom.cutoff	Nomination cutoff percentile. Range (0, 1). Must not be exactly 0 or 1. Defaults to 1e-7 for a single- stage identification system.
mu	Population mean true score on a standardized (z-score) metric. Defaults to zero.

Details

See also d_identified for the normalized density, p_identified for the cumulative density function, and r_identified for random generation.

Examples

# one-stage identification program
# returns the true score
q_identified(percentile = .1, relyt = .9, test.cutoff = .9)

# one-stage identification program
# returns the observed score
q_identified(percentile = .1, test.cutoff = .9)

# two-stage identification program
#  returns the true score
q_identified(
  percentile = .9, relyt = .95, valid = .6,
  test.cutoff = .975, nom.cutoff = .9
)

mcbeem/giftedCalcs documentation built on May 3, 2022, 3:34 a.m.