subscore.corr {subscore}

Computing correlation indices for subscores and the total score.

Description

This function computes Cronbach's Alpha and Stratified Alpha (Cronbach et al., 1965) <doi: 10.1177/001316446502500201>. Disattenuated correlations are also provided.

Usage

subscore.corr(test.data)

Arguments

test.data

A list that contains item responses of all subtests and the entire test, which can be obtained using function ’data.prep’.

Value

summary

Summary of obtained subscores (e.g., mean, sd).

correlation

Correlation indices as indicated above.

References

Cronbach, L., Schonenman, P., & McKie, D. (1965). "Alpha coefficients for stratified-parallel tests." Educational and Psychological Measurement, 25, 291-282. doi: 10.1177/001316446502500201.

Examples

# Transferring scored response data to the required list format
test.data<-data.prep(scored.data,c(3,15,15,20),
                     c("Algebra","Geometry","Measurement", "Math"))
  
#Estimate true subscores using Haberman's method based on observed subscores     
subscore.corr(test.data) 
       
subscore.s(test.data)$summary
subscore.s(test.data)$correlation