correct_glass_bias | R Documentation |

`\Delta`

valuesCorrect for small-sample bias in Glass' `\Delta`

values.

```
correct_glass_bias(delta, nc, ne, use_pooled_sd = rep(FALSE, length(delta)))
```

`delta` |
Vector of Glass' |

`nc` |
Vector of control-group sample sizes. |

`ne` |
Vector of experimental-group sample sizes. |

`use_pooled_sd` |
Logical vector determining whether the pooled standard deviation was used ( |

The bias correction is estimated as:

`\Delta_{c}=\Delta_{obs}\frac{\Gamma\left(\frac{n_{control}-1}{2}\right)}{\Gamma\left(\frac{n_{control}-1}{2}\right)\Gamma\left(\frac{n_{control}-2}{2}\right)}`

where `\Delta`

is the observed effect size, `\Delta_{c}`

is the
corrected estimate of `\Delta`

,
`n_{control}`

is the control-group sample size, and
`\Gamma()`

is the gamma function.

Vector of d values corrected for small-sample bias.

Hedges, L. V. (1981). Distribution theory for Glass’s estimator of effect
size and related estimators. *Journal of Educational Statistics, 6*(2),
107–128. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.2307/1164588")}

```
correct_glass_bias(delta = .3, nc = 30, ne = 30)
```

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