/**
* NORMDIST
*
* Returns the normal distribution for the specified mean and standard deviation. This
* function has a very wide range of applications in statistics, including hypothesis
* testing.
*
* @param float $value
* @param float $mean Mean Value
* @param float $stdDev Standard Deviation
* @param boolean $cumulative
* @return float
*
*/
public static function NORMDIST($value, $mean, $stdDev, $cumulative)
{
$value = PHPExcel_Calculation_Functions::flattenSingleValue($value);
$mean = PHPExcel_Calculation_Functions::flattenSingleValue($mean);
$stdDev = PHPExcel_Calculation_Functions::flattenSingleValue($stdDev);
if (is_numeric($value) && is_numeric($mean) && is_numeric($stdDev)) {
if ($stdDev < 0) {
return PHPExcel_Calculation_Functions::NaN();
}
if (is_numeric($cumulative) || is_bool($cumulative)) {
if ($cumulative) {
return 0.5 * (1 + PHPExcel_Calculation_Engineering::_erfVal(($value - $mean) / ($stdDev * sqrt(2))));
} else {
return 1 / (SQRT2PI * $stdDev) * exp(0 - pow($value - $mean, 2) / (2 * ($stdDev * $stdDev)));
}
}
}
return PHPExcel_Calculation_Functions::VALUE();
}
public function testGetConversionMultipliers()
{
$result = PHPExcel_Calculation_Engineering::getConversionMultipliers();
$this->assertInternalType('array', $result);
}