Feature Relevance inWard’s Hierarchical Clustering Using the Lp Norm
Résumé
Cronbach's alpha is an estimate of the reliability of a test score if the items are essentially tau-equivalent. Several authors have derived results that provide al-ternative interpretations of alpha. These interpretations are also valid if essential tau-equivalency does not hold. For example, alpha is the mean of all split-half reliabilities if the test is split into two halves that are equal in size. This note presents several con-nections between Cronbach's alpha and the Spearman-Brown formula. The results provide new interpretations of Cronbach's alpha, the stepped down alpha, and stan-dardized alpha, that are also valid in the case that essential tau-equivalency or parallel equivalency do not hold. The main result is that the stepped down alpha is a weighted average of the alphas of all subtests of a specific size, where the weights are the de-nominators of the subtest alphas. Thus, the stepped down alpha can be interpreted as an average subtest alpha. Furthermore, we may calculate the stepped down alpha without using the Spearman-Brown formula.
Auteurs, date et publication :
Auteurs
Publication : Journal of Classification
Date : 2023
Volume : 32
Issue : March
Pages : 46–62