sd_identified: Standard deviation of the conditional distribution of true or...

In mcbeem/giftedCalcs: Psychometrics for Gifted Program Identification

Standard deviation of the conditional distribution of true or observed scores for identified students

Description

sd_identified calculates the standard deviation of the ability true score distribution for identified students.

Usage

sd_identified(
  relyt = 1,
  test.cutoff,
  valid = 1e-07,
  nom.cutoff = 1e-07,
  mu = 0
)

Arguments

relyt	Confirmatory test reliability coefficient. Range (0, 1]. Must not be exactly 0. Defaults to 1; in this case, x is assumed to be an observed score. If an alternative value is supplied for relyt, x is assumed to be 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.
nom.cutoff	Nomination cutoff percentile. Range (0, 1). Must not be exactly 0 or 1.
mu	Population mean true score on a standardized (z-score) metric. Defaults to zero.

Examples

# std dev for true scores
sd_identified(
  relyt = .9, valid = .8,
  test.cutoff = .9, nom.cutoff = .5, mu = 0
)

# std dev for observed scores
15 * (sd_identified(
  valid = .8,
  test.cutoff = .9, nom.cutoff = .5, mu = 0
))

mcbeem/giftedCalcs documentation built on Nov. 29, 2024, 3:48 a.m.