meta.sub.cronbach {vcmeta} | R Documentation |
Confidence interval for a subgroup difference in average Cronbach reliabilities
Description
Computes the estimate, standard error, and confidence interval for a difference in average Cronbach reliability coefficients for two mutually exclusive subgroups of studies. Each set can have one or more studies. The number of measurements used to compute the sample reliablity coefficient is assumed to be the same for all studies.
Usage
meta.sub.cronbach(alpha, n, rel, r, group)
Arguments
alpha |
alpha level for 1-alpha confidence |
n |
vector of sample sizes |
rel |
vector of estimated Cronbach reliabilities |
r |
number of measurements (e.g., items) |
group |
vector of group indicators:
|
Value
Returns a matrix with three rows:
Row 1 - estimate for Set A
Row 2 - estimate for Set B
Row 3 - estimate for difference, Set A - Set B
The columns are:
Estimate - estimated average correlation or difference
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(120, 170, 150, 135)
rel <- c(.89, .87, .73, .71)
group <- c(1, 1, 2, 2)
r <- 10
meta.sub.cronbach(.05, n, rel, r, group)
# Should return:
# Estimate SE LL UL
# Set A: 0.88 0.01068845 0.8581268 0.8999386
# Set B: 0.72 0.02515130 0.6684484 0.7668524
# Set A - Set B: 0.16 0.02732821 0.1082933 0.2152731