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compute.es (version 0.2.1)

failes: Failure groups to Effect Size

Description

Converts binary data, that only reported the number of 'failure' groups, to $d$ (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

failes(B, D, n.1, n.0)

Arguments

B
Treatment failure.
D
Non-treatment failure.
n.1
Treatment sample size.
n.0
Control/comparison sample size.

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.

Details

This formula will first compute an odds ratio and then a log odds and its variance. From there, Cohen's $d$ is computed and the remaining effect size estimates are then derived from $d$. Computing the odds ratio involves $$or= \frac{p_{1}(1-p_{2})} {p_{2}(1-p_{1})}$$ The conversion to a log odds and its variance is defined as $$ln(o)= log(or)$$ $$v_{ln(o)}= \frac{1} {A}+ \frac{1} {B}+ \frac{1} {C}+ \frac{1} {D}$$

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.

See Also

lores, propes