ci.cronbach2 {statpsych} | R Documentation |
Confidence interval for a difference in Cronbach reliabilities in a 2-group design
Description
Computes a confidence interval for a difference in population Cronbach reliability coefficients in a 2-group design. The number of measurements (e.g., items or raters) used in each group need not be equal.
Usage
ci.cronbach2(alpha, rel1, rel2, r1, r2, n1, n2)
Arguments
alpha |
alpha level for 1-alpha confidence |
rel1 |
estimated Cronbach reliability for group 1 |
rel2 |
estimated Cronbach reliability for group 2 |
r1 |
number of measurements used in group 1 |
r2 |
number of measurements used in group 2 |
n1 |
sample size for group 1 |
n2 |
sample size for group 2 |
Value
Returns a 1-row matrix. The columns are:
Estimate - estimated reliability difference
LL - lower limit of the confidence interval
UL - upper limit of the confidence interval
References
Bonett DG, Wright TA (2015). “Cronbach's alpha reliability: Interval estimation, hypothesis testing, and sample size planning.” Journal of Organizational Behavior, 36(1), 3–15. ISSN 08943796, doi:10.1002/job.1960.
Examples
ci.cronbach2(.05, .88, .76, 8, 8, 200, 250)
# Should return:
# Estimate LL UL
# 0.12 0.06973411 0.173236