Examples of org.apache.commons.math.stat.descriptive.moment.Skewness

Package org.apache.commons.math.stat.descriptive.moment

Examples of org.apache.commons.math.stat.descriptive.moment.Skewness

org.apache.commons.math.stat.descriptive.moment.Skewness
Computes the skewness of the available values.
We use the following (unbiased) formula to define skewness:

skewness = [n / (n -1) (n - 2)] sum[(x_i - mean)^3] / std^3

where n is the number of values, mean is the {@link Mean} and std is the{@link StandardDeviation}
Note that this implementation is not synchronized. If multiple threads access an instance of this class concurrently, and at least one of the threads invokes the increment() or clear() method, it must be synchronized externally.
@version $Revision: 1006299 $ $Date: 2010-10-10 16:47:17 +0200 (dim. 10 oct. 2010) $

    public void testInteraction() {


        FourthMoment m4 = new FourthMoment();
        Mean m = new Mean(m4);
        Variance v = new Variance(m4);
        Skewness s= new Skewness(m4);
        Kurtosis k = new Kurtosis(m4);


        for (int i = 0; i < testArray.length; i++){
            m4.increment(testArray[i]);
        }


        assertEquals(mean,m.getResult(),tolerance);
        assertEquals(var,v.getResult(),tolerance);
        assertEquals(skew ,s.getResult(),tolerance);
        assertEquals(kurt,k.getResult(),tolerance);


    }

View Full Code Here

    public void testInteraction() {
        
        FourthMoment m4 = new FourthMoment();
        Mean m = new Mean(m4);
        Variance v = new Variance(m4);
        Skewness s= new Skewness(m4);
        Kurtosis k = new Kurtosis(m4);


        for (int i = 0; i < testArray.length; i++){
            m4.increment(testArray[i]);
        }
        
        assertEquals(mean,m.getResult(),tolerance);
        assertEquals(var,v.getResult(),tolerance);
        assertEquals(skew ,s.getResult(),tolerance);
        assertEquals(kurt,k.getResult(),tolerance);


    }

View Full Code Here

     * measure of the assymetry of a given distribution.
     * @return The skewness, Double.NaN if no values have been added 
     * or 0.0 for a value set &lt;=2. 
     */
    public double getSkewness() {
        return apply(new Skewness());
    }

View Full Code Here

    public void testInteraction() {


        FourthMoment m4 = new FourthMoment();
        Mean m = new Mean(m4);
        Variance v = new Variance(m4);
        Skewness s= new Skewness(m4);
        Kurtosis k = new Kurtosis(m4);


        for (int i = 0; i < testArray.length; i++){
            m4.increment(testArray[i]);
        }


        assertEquals(mean,m.getResult(),tolerance);
        assertEquals(var,v.getResult(),tolerance);
        assertEquals(skew ,s.getResult(),tolerance);
        assertEquals(kurt,k.getResult(),tolerance);


    }

View Full Code Here

    public void testInteraction() {
        
        FourthMoment m4 = new FourthMoment();
        Mean m = new Mean(m4);
        Variance v = new Variance(m4);
        Skewness s= new Skewness(m4);
        Kurtosis k = new Kurtosis(m4);


        for (int i = 0; i < testArray.length; i++){
            m4.increment(testArray[i]);
        }
        
        assertEquals(mean,m.getResult(),tolerance);
        assertEquals(var,v.getResult(),tolerance);
        assertEquals(skew ,s.getResult(),tolerance);
        assertEquals(kurt,k.getResult(),tolerance);


    }

View Full Code Here

     * measure of the assymetry of a given distribution.
     * @return The skewness, Double.NaN if no values have been added 
     * or 0.0 for a value set &lt;=2. 
     */
    public double getSkewness() {
        return apply(new Skewness());
    }

View Full Code Here

    public void testInteraction() {
        
        FourthMoment m4 = new FourthMoment();
        Mean m = new Mean(m4);
        Variance v = new Variance(m4);
        Skewness s= new Skewness(m4);
        Kurtosis k = new Kurtosis(m4);


        for (int i = 0; i < testArray.length; i++){
            m4.increment(testArray[i]);
        }
        
        assertEquals(mean,m.getResult(),tolerance);
        assertEquals(var,v.getResult(),tolerance);
        assertEquals(skew ,s.getResult(),tolerance);
        assertEquals(kurt,k.getResult(),tolerance);


    }

View Full Code Here

    public void testInteraction() {
        
        FourthMoment m4 = new FourthMoment();
        Mean m = new Mean(m4);
        Variance v = new Variance(m4);
        Skewness s= new Skewness(m4);
        Kurtosis k = new Kurtosis(m4);


        for (int i = 0; i < testArray.length; i++){
            m4.increment(testArray[i]);
        }
        
        assertEquals(mean,m.getResult(),tolerance);
        assertEquals(var,v.getResult(),tolerance);
        assertEquals(skew ,s.getResult(),tolerance);
        assertEquals(kurt,k.getResult(),tolerance);


    }

View Full Code Here

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Related Classes of org.apache.commons.math.stat.descriptive.moment.Skewness

org.apache.commons.math.stat.descriptive.DescriptiveStatistics

org.apache.commons.math.stat.descriptive.InteractionTest

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