Robust Cronbach's alpha

Description

Calculate alpha for a given data set.

Usage

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cronbach(y, varphi = 0.1, se = FALSE, complete = FALSE)

Arguments

y

Data

varphi

Downweight rate

se

Whether to estimate standard error. It will take significant more time if se is requested.

complete

Calculate alpha only based on complete data (lisewise deletion)

Author(s)

Zhiyong Zhang and Ke-Hai Yuan

References

Zhang, Z. & Yuan, K.-H. (2013). Robust Cronbach's alpha.

Examples

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data(holzinger)
spatial<-holzinger[, c('visual', 'cubes', 'paper', 'lozenge', 'paperrev','flagssub')]
verbal<-holzinger[, c('general', 'paragrap', 'sentence', 'wordc', 'wordm')]
speed<-holzinger[, c('add', 'code', 'counting', 'straight')]
memory<-holzinger[, c('wordr', 'numberr', 'figurer', 'object', 'numberf', 'figurew')]

alpha.spatial<-cronbach(spatial, varphi=.01)