meta.ave.stdmean.ps {vcmeta} | R Documentation |
Confidence interval for an average standardized mean difference from paired-samples studies
Description
Computes the estimate, standard error, and confidence interval for an average standardized mean difference from two or more paired-samples studies. Unweighted variances and single group variance are options for the standardizer. Equality of variances within or across studies is not assumed.
Usage
meta.ave.stdmean.ps(alpha, m1, m2, sd1, sd2, cor, n, stdzr, bystudy = TRUE)
Arguments
alpha |
alpha level for 1-alpha confidence |
m1 |
vector of estimated means for measurement 1 |
m2 |
vector of estimated means for measurement 2 |
sd1 |
vector of estimated SDs for measurement 1 |
sd2 |
vector of estimated SDs for measurement 2 |
cor |
vector of estimated correlations for paired measurements |
n |
vector of sample sizes |
stdzr |
|
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 (2009). “Meta-analytic interval estimation for standardized and unstandardized mean differences.” Psychological Methods, 14(3), 225–238. ISSN 1939-1463, doi:10.1037/a0016619.
Examples
m1 <- c(23.9, 24.1)
m2 <- c(25.1, 26.9)
sd1 <- c(1.76, 1.58)
sd2 <- c(2.01, 1.76)
cor <- c(.78, .84)
n <- c(25, 30)
meta.ave.stdmean.ps(.05, m1, m2, sd1, sd2, cor, n, 1, bystudy = TRUE)
# Should return:
# Estimate SE LL UL
# Average -1.1931045 0.1568034 -1.500433 -0.8857755
# Study 1 -0.6818182 0.1773785 -1.029474 -0.3341628
# Study 2 -1.7721519 0.2586234 -2.279044 -1.2652594