a.mes: Mean Values from ANCOVA F-statistic to Effect Size
Description
Converts an ANCOVA F-statistic to an effect size of $d$ (mean difference), $g$ (unbiased estimate of $d$), $r$ (correlation coefficient), $z'$ (Fisher's $z$), and log odds ratio. The variances of these estimates are also computed.Usage
a.mes(m.1.adj, m.2.adj, sd.adj, n.1, n.2, R, q)
Arguments
m.1.adj
Adjusted mean of treatment group from ANCOVA.
m.2.adj
Adjusted mean of comparison group from ANCOVA.
sd.adj
Adjusted standard deviation.
n.1
Treatment group sample size.
n.2
Comparison group sample size.
R
Covariate outcome correlation or multiple correlation.
Value
- dStandardized mean difference ($d$).
- var.dVariance of $d$.
- gUnbiased estimate of $d$.
- var.gVariance of $g$.
- rCorrelation coefficient.
- var.rVariance of $r$.
- log.oddsLog odds ratio.
- var.log.oddsVariance of log odds ratio.
- nTotal sample size.
References
Borenstein (2009). Effect sizes for continuous data. In H. Cooper, L. V. Hedges, & J. C. Valentine (Eds.), The handbook of research synthesis and meta analysis (pp. 279-293). New York: Russell Sage Foundation.