<?php
namespace PhpOffice\PhpSpreadsheet\Calculation\Statistical\Distributions;
use PhpOffice\PhpSpreadsheet\Calculation\Exception;
use PhpOffice\PhpSpreadsheet\Calculation\Functions;
use PhpOffice\PhpSpreadsheet\Calculation\MathTrig\Combinations;
class HyperGeometric
{
/**
* HYPGEOMDIST.
*
* Returns the hypergeometric distribution. HYPGEOMDIST returns the probability of a given number of
* sample successes, given the sample size, population successes, and population size.
*
* @param mixed $sampleSuccesses Integer number of successes in the sample
* @param mixed $sampleNumber Integer size of the sample
* @param mixed $populationSuccesses Integer number of successes in the population
* @param mixed $populationNumber Integer population size
*
* @return float|string
*/
public static function distribution($sampleSuccesses, $sampleNumber, $populationSuccesses, $populationNumber)
{
$sampleSuccesses = Functions::flattenSingleValue($sampleSuccesses);
$sampleNumber = Functions::flattenSingleValue($sampleNumber);
$populationSuccesses = Functions::flattenSingleValue($populationSuccesses);
$populationNumber = Functions::flattenSingleValue($populationNumber);
try {
$sampleSuccesses = DistributionValidations::validateInt($sampleSuccesses);
$sampleNumber = DistributionValidations::validateInt($sampleNumber);
$populationSuccesses = DistributionValidations::validateInt($populationSuccesses);
$populationNumber = DistributionValidations::validateInt($populationNumber);
} catch (Exception $e) {
return $e->getMessage();
}
if (($sampleSuccesses < 0) || ($sampleSuccesses > $sampleNumber) || ($sampleSuccesses > $populationSuccesses)) {
return Functions::NAN();
}
if (($sampleNumber <= 0) || ($sampleNumber > $populationNumber)) {
return Functions::NAN();
}
if (($populationSuccesses <= 0) || ($populationSuccesses > $populationNumber)) {
return Functions::NAN();
}
$successesPopulationAndSample = (float) Combinations::withoutRepetition($populationSuccesses, $sampleSuccesses);
$numbersPopulationAndSample = (float) Combinations::withoutRepetition($populationNumber, $sampleNumber);
$adjustedPopulationAndSample = (float) Combinations::withoutRepetition(
$populationNumber - $populationSuccesses,
$sampleNumber - $sampleSuccesses
);
return $successesPopulationAndSample * $adjustedPopulationAndSample / $numbersPopulationAndSample;
}
}