public static double kurtosis(FlatDataCollection flatDataCollection) {
	    int n = count(flatDataCollection);
        if(n<=3) {
            throw new IllegalArgumentException("The provided collection must have more than 3 elements.");
        }
        
        double mean = mean(flatDataCollection);
        
        double m4 = moment(flatDataCollection, 4, mean);
        double m2 = moment(flatDataCollection, 2, mean);        

        /*
        g2=m4/(m2*m2);

        kurtosis=((n-1.0)/((n-2.0)*(n-3.0)))*((n+1.0)*g2 +6.0);
        //kurtosis=g2/(n-1.0)-3.0;
        //kurtosis=g2;
        */
        
        double s = (n/(n-1.0))*m2;
        
        double Mcapital4=n*m4;
        double Mcapital2=n*m2;
        double kurtosis=(n*(n+1.0)*Mcapital4-3*Mcapital2*Mcapital2*(n-1.0))/((n-1.0)*(n-2.0)*(n-3.0)*s*s);
        
        return kurtosis;
    }
public static double kurtosis ( FlatDataCollection flatDataCollection ) { int n = count ( flatDataCollection ) ; if ( n <= 3 ) { throw new IllegalArgumentException ( "The provided collection must have more than 3 elements." ) ; } double mean = mean ( flatDataCollection ) ; double m4 = moment ( flatDataCollection , 4 , mean ) ; double m2 = moment ( flatDataCollection , 2 , mean ) ; double s = ( n / ( n - 1.0 ) ) * m2 ; double Mcapital4 = n * m4 ; double Mcapital2 = n * m2 ; double kurtosis = ( n * ( n + 1.0 ) * Mcapital4 - 3 * Mcapital2 * Mcapital2 * ( n - 1.0 ) ) / ( ( n - 1.0 ) * ( n - 2.0 ) * ( n - 3.0 ) * s * s ) ; return kurtosis ; }
Calculates Kurtosis. Uses a formula similar to SPSS as suggested in their documentation (local help)

@param flatDataCollection
@return