size.test.cronbach2 {statpsych} | R Documentation |
Computes the sample size required to test a difference in population Cronbach reliability coefficients with desired power in a 2-group design.
size.test.cronbach2(alpha, pow, rel1, rel2, r)
alpha |
alpha level for hypothesis test |
pow |
desired power |
rel1 |
reliability planning value for group 1 |
rel2 |
reliability planning value for group 2 |
r |
number of measurements (items, raters) |
Returns the required sample size for each group
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.
size.test.cronbach2(.05, .80, .85, .70, 8)
# Should return:
# Sample size per group
# 77