private function getStandardDeviation($array)
    {
        $sdSquare = function ($x, $mean) {
            return pow($x - $mean, 2);
        };
        // avoid division by 0
        $nbData = count($array) > 1 ? count($array) - 1 : 1;
        $fillNbData = count($array) > 0 ? count($array) : 1;

        return sqrt(
          array_sum(
            array_map(
              $sdSquare,
              $array,
              array_fill(0, count($array), (array_sum($array) / $fillNbData))
            )
          ) / $nbData
        );
    }
private function getStandardDeviation($array)
    {
        $sdSquare = function ($x, $mean) {
            return pow($x - $mean, 2);
        };
        // avoid division by 0
        $nbData = count($array) > 1 ? count($array) - 1 : 1;
        $fillNbData = count($array) > 0 ? count($array) : 1;

        return sqrt(
          array_sum(
            array_map(
              $sdSquare,
              $array,
              array_fill(0, count($array), (array_sum($array) / $fillNbData))
            )
          ) / $nbData
        );
    }
private function getStandardDeviation ( $ array ) { $ sdSquare = function ( $ x , $ mean ) { return pow ( $ x - $ mean , 2 ) ; } ; // avoid division by 0 $ nbData = count ( $ array ) > 1 ? count ( $ array ) - 1 : 1 ; $ fillNbData = count ( $ array ) > 0 ? count ( $ array ) : 1 ; return sqrt ( array_sum ( array_map ( $ sdSquare , $ array , array_fill ( 0 , count ( $ array ) , ( array_sum ( $ array ) / $ fillNbData ) ) ) ) / $ nbData ) ; }
Get standard deviation for the discrimination coefficient.

@param type $array

@return type
Get standard deviation for the discrimination coefficient .