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exametrika (version 1.1.0)

AlphaCoefficient: Alpha Coefficient

Description

This function computes Tau-Equivalent Measurement, also known as Cronbach's alpha coefficient, for a given data set.

Usage

AlphaCoefficient(x, na = NULL, Z = NULL, w = NULL)

Value

For a correlation/covariance matrix input, returns a single numeric value representing the alpha coefficient. For a data matrix input, returns a list with three components:

  • AlphaCov: Alpha coefficient calculated from covariance matrix

  • AlphaPhi: Alpha coefficient calculated from phi coefficient matrix

  • AlphaTetrachoric: Alpha coefficient calculated from tetrachoric correlation matrix

Arguments

x

This should be a data matrix or a Covariance/Phi/Tetrachoric matrix.

na

This parameter identifies the numbers or characters that should be treated as missing values when 'x' is a data matrix.

Z

This parameter represents a missing indicator matrix. It is only needed if 'x' is a data matrix.

w

This parameter is an item weight vector. It is only required if 'x' is a data matrix.

References

Cronbach, L. J. (1951). Coefficient alpha and the internal structure of a test. Psychometrika, 16,297–334.