subscore (version 3.3)

subscore.corr: 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 <U+2019>data.prep<U+2019>.

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

# NOT RUN {
# 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
# }