(self)
return 0
get current standard deviation
get current standard deviation
get current standard deviation
def get_stddev(self):
        "get current standard deviation"
        if self.counter > 0:
            return math.sqrt(self.get_var())
        return 0
def get_stddev ( self ) : if self . counter > 0 : return math . sqrt ( self . get_var ( ) ) return 0