Viewing file:  Confidence.php (1.75 KB) -rw-r--r--
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<?php
namespace PhpOffice\PhpSpreadsheet\Calculation\Statistical;
use PhpOffice\PhpSpreadsheet\Calculation\ArrayEnabled;
use PhpOffice\PhpSpreadsheet\Calculation\Exception;
use PhpOffice\PhpSpreadsheet\Calculation\Functions;
use PhpOffice\PhpSpreadsheet\Calculation\Information\ExcelError;
class Confidence
{
use ArrayEnabled;
/**
* CONFIDENCE.
*
* Returns the confidence interval for a population mean
*
* @param mixed $alpha As a float
* Or can be an array of values
* @param mixed $stdDev Standard Deviation as a float
* Or can be an array of values
* @param mixed $size As an integer
* Or can be an array of values
*
* @return array|float|string
* If an array of numbers is passed as an argument, then the returned result will also be an array
* with the same dimensions
*/
public static function CONFIDENCE($alpha, $stdDev, $size)
{
if (is_array($alpha) || is_array($stdDev) || is_array($size)) {
return self::evaluateArrayArguments([self::class, __FUNCTION__], $alpha, $stdDev, $size);
}
try {
$alpha = StatisticalValidations::validateFloat($alpha);
$stdDev = StatisticalValidations::validateFloat($stdDev);
$size = StatisticalValidations::validateInt($size);
} catch (Exception $e) {
return $e->getMessage();
}
if (($alpha <= 0) || ($alpha >= 1) || ($stdDev <= 0) || ($size < 1)) {
return ExcelError::NAN();
}
/** @var float */
$temp = Distributions\StandardNormal::inverse(1 - $alpha / 2);
return Functions::scalar($temp * $stdDev / sqrt($size));
}
}
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