var_error_g {psychmeta} | R Documentation |
Estimate the error variance Hedges's g
values
Description
Allows for error variance to be estimated using total sample size of both groups being compared (in this case, supply sample sizes using only the n1 argument) or using separate sample sizes for group 1 and group 2 (i.e., the groups being compared; in this case, supply sample sizes using both the n1 and n2 arguments).
Usage
var_error_g(g, n1, n2 = NA, a_method = c("gamma", "approx"))
Arguments
g |
Vector of Hedges's |
n1 |
Vector of sample sizes from group 1 (or the total sample size with the assumption that groups are of equal size, if no group 2 sample size is supplied). |
n2 |
Vector of sample sizes from group 2. |
a_method |
Method used to correct the bias in Cohen's d to convert to Hedges's g. Options are "gamma" (default) for the exact method based on the gamma function (Hedges & Olkin, 1985) or "approx" for the computationally trivial approximation (Borenstein et al., 2006). |
Value
A vector of sampling-error variances.
References
Hedges, L. V., & Olkin, I. (1985). Statistical methods for meta-analysis. Academic Press. p. 104
Borenstein, M., Hedges, L. V., Higgins, J. P. T., & Rothstein, H. R. (2009). Introduction to meta-analysis. Wiley. p. 27.
Examples
var_error_g(g = 1, n1 = 30, n2 = 30)
var_error_g(g = 1, n1 = 60, n2 = NA)