ci.cronbach {statpsych} | R Documentation |
Computes a confidence interval for a population Cronbach reliability. The point estimate of Cronbach's reliability assumes essentially tau-equivalent measurements and this confidence interval assumes parallel measurements.
ci.cronbach(alpha, rel, r, n)
alpha |
alpha level for 1-alpha confidence |
rel |
sample value of Cronbach's reliability |
r |
number of measurements (items, raters, etc.) |
n |
sample size |
Returns a 1-row matrix. The columns are:
LL - lower limit of the confidence interval
UL - upper limit of the confidence interval
Feldt LS (1965). “The approximate sampling distribution of Kuder-Richardson reliability coefficient twenty.” Psychometrika, 30(3), 357–370. ISSN 0033-3123, doi: 10.1007/BF02289499.
ci.cronbach(.05, .85, 7, 89) # Should return: # LL UL # [1,] 0.7971254 0.8931436