| public static hedgesG ( number $μ₁, number $μ₂, number $s₁, number $s₂, number $n₁, number $n₂ ) : number | ||
| $μ₁ | number | Mean of sample population 1 |
| $μ₂ | number | Mean of sample population 2 |
| $s₁ | number | Standard deviation of sample population 1 |
| $s₂ | number | Standard deviation of sample population 2 |
| $n₁ | number | Sample size of sample popluation 1 |
| $n₂ | number | Sample size of sample popluation 2 |
| return | number | |
public static function hedgesG($μ₁, $μ₂, $s₁, $s₂, $n₁, $n₂)
{
// Variance of each data set
$s₁² = $s₁ * $s₁;
$s₂² = $s₂ * $s₂;
// Pooled standard deviation
$⟮n₁ − 1⟯s₁² ＋ ⟮n₂ − 1⟯s₂² = ($n₁ - 1) * $s₁² + ($n₂ - 1) * $s₂²;
$⟮n₁ ＋ n₂ − 2⟯ = $n₁ + $n₂ - 2;
$s＊ = sqrt($⟮n₁ − 1⟯s₁² ＋ ⟮n₂ − 1⟯s₂² / $⟮n₁ ＋ n₂ − 2⟯);
// g
$g = ($μ₁ - $μ₂) / $s＊;
// Unbiased g
return (1 - 3 / (4 * ($n₁ + $n₂) - 9)) * $g;
}