This function computes Tau-Equivalent Measurement, also known as Cronbach's alpha coefficient, for a given data set.
AlphaCoefficient(x, na = NULL, Z = NULL, w = NULL)
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
This should be a data matrix or a Covariance/Phi/Tetrachoric matrix.
This parameter identifies the numbers or characters that should be treated as missing values when 'x' is a data matrix.
This parameter represents a missing indicator matrix. It is only needed if 'x' is a data matrix.
This parameter is an item weight vector. It is only required if 'x' is a data matrix.
Cronbach, L. J. (1951). Coefficient alpha and the internal structure of a test. Psychometrika, 16,297–334.