| meta.ave.cronbach {vcmeta} | R Documentation |
Confidence interval for an average Cronbach alpha reliability
Description
Computes the estimate, standard error, and confidence interval for an average Cronbach reliability coefficient from two or more studies.
Usage
meta.ave.cronbach(alpha, n, rel, r, bystudy = TRUE)
Arguments
alpha |
alpha level for 1-alpha confidence |
n |
vector of sample sizes |
rel |
vector of sample reliabilities |
r |
number of measurements (e.g., items) used to compute each reliability |
bystudy |
logical to also return each study estimate (TRUE) or not |
Value
Returns a matrix. The first row is the average estimate across all studies. If bystudy is TRUE, there is 1 additional row for each study. The matrix has the following columns:
Estimate - estimated effect size
SE - standard error
LL - lower limit of the confidence interval
UL - upper limit of the confidence interval
References
Bonett DG (2010). “Varying coefficient meta-analytic methods for alpha reliability.” Psychological Methods, 15(4), 368–385. ISSN 1939-1463, doi:10.1037/a0020142.
Examples
n <- c(583, 470, 546, 680)
rel <- c(.91, .89, .90, .89)
meta.ave.cronbach(.05, n, rel, 10, bystudy = TRUE)
# Should return:
# Estimate SE LL UL
# Average 0.8975 0.003256081 0.8911102 0.9038592
# Study 1 0.9100 0.005566064 0.8985763 0.9204108
# Study 2 0.8900 0.007579900 0.8743616 0.9041013
# Study 3 0.9000 0.006391375 0.8868623 0.9119356
# Study 4 0.8900 0.006297549 0.8771189 0.9018203