tt.ancova_to_es: t-test Value from ANCOVA to Effect Size
Description
Converts a t-test value from ANCOVA 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
tt.ancova_to_es(t, n.1, n.2, R, q)
Arguments
t
t-test value reported in primary study.
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.