/** * KURT * * Returns the kurtosis of a data set. Kurtosis characterizes the relative peakedness * or flatness of a distribution compared with the normal distribution. Positive * kurtosis indicates a relatively peaked distribution. Negative kurtosis indicates a * relatively flat distribution. * * @param array Data Series * @return float */ public static function KURT() { $aArgs = PHPExcel_Calculation_Functions::flattenArray(func_get_args()); $mean = PHPExcel_Calculation_Functions::AVERAGE($aArgs); $stdDev = PHPExcel_Calculation_Functions::STDEV($aArgs); if ($stdDev > 0) { $count = $summer = 0; // Loop through arguments foreach ($aArgs as $arg) { // Is it a numeric value? if (is_numeric($arg) && !is_string($arg)) { $summer += pow(($arg - $mean) / $stdDev, 4); ++$count; } } // Return if ($count > 3) { return $summer * ($count * ($count + 1) / (($count - 1) * ($count - 2) * ($count - 3))) - 3 * pow($count - 1, 2) / (($count - 2) * ($count - 3)); } } return self::$_errorCodes['divisionbyzero']; }