public static function likelihoodRatioSS(float $sensitivity, float $specificity) : array
{
if ($sensitivity > 1.0 || $specificity > 1.0) {
throw new Exception\OutOfBoundsException('Sensitivity and specificity must be <= 1.0');
}
// LL+ Positive likelihood ratio
$LL＋ = $sensitivity / (1 - $specificity);
// LL- Negative likelihood ratio
$LL− = (1 - $sensitivity) / $specificity;
return ['LL+' => $LL＋, 'LL-' => $LL−];
}