question: public double skewness ( ) { double mu = mean ( ) ; double devsum = 0 ; double wsum = 0 ; int size = values . size ( ) ; for ( int i = 0 ; i < size ; i ++ ) { double dev = values . get ( i ) - mu ; devsum += dev * dev * dev * weights . get ( i ) ; wsum += weights . get ( i ) ; } double mu3 = devsum / wsum ; double s3 = Math . pow ( variance ( ) , 3.0 / 2.0 ) ; return mu3 / s3 ; }
target:  Returns the (weighted) skewness of all samples.