<?php
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namespace PhpOffice\PhpSpreadsheet\Calculation\Statistical\Distributions;
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use PhpOffice\PhpSpreadsheet\Calculation\ArrayEnabled;
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use PhpOffice\PhpSpreadsheet\Calculation\Exception;
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use PhpOffice\PhpSpreadsheet\Calculation\Information\ExcelError;
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class F
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{
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use ArrayEnabled;
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/**
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* F.DIST.
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*
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* Returns the F probability distribution.
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* You can use this function to determine whether two data sets have different degrees of diversity.
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* For example, you can examine the test scores of men and women entering high school, and determine
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* if the variability in the females is different from that found in the males.
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*
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* @param mixed $value Float value for which we want the probability
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* Or can be an array of values
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* @param mixed $u The numerator degrees of freedom as an integer
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* Or can be an array of values
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* @param mixed $v The denominator degrees of freedom as an integer
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* Or can be an array of values
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* @param mixed $cumulative Boolean value indicating if we want the cdf (true) or the pdf (false)
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* Or can be an array of values
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*
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* @return array|float|string If an array of numbers is passed as an argument, then the returned result will also be an array
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* with the same dimensions
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*/
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public static function distribution(mixed $value, mixed $u, mixed $v, mixed $cumulative): array|string|float
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{
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if (is_array($value) || is_array($u) || is_array($v) || is_array($cumulative)) {
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return self::evaluateArrayArguments([self::class, __FUNCTION__], $value, $u, $v, $cumulative);
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}
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try {
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$value = DistributionValidations::validateFloat($value);
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$u = DistributionValidations::validateInt($u);
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$v = DistributionValidations::validateInt($v);
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$cumulative = DistributionValidations::validateBool($cumulative);
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} catch (Exception $e) {
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return $e->getMessage();
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}
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if ($value < 0 || $u < 1 || $v < 1) {
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return ExcelError::NAN();
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}
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if ($cumulative) {
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$adjustedValue = ($u * $value) / ($u * $value + $v);
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return Beta::incompleteBeta($adjustedValue, $u / 2, $v / 2);
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}
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return (Gamma::gammaValue(($v + $u) / 2)
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/ (Gamma::gammaValue($u / 2) * Gamma::gammaValue($v / 2)))
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* (($u / $v) ** ($u / 2))
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* (($value ** (($u - 2) / 2)) / ((1 + ($u / $v) * $value) ** (($u + $v) / 2)));
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}
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}
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