All Implemented Interfaces:
Serializable, StorelessUnivariateStatistic, UnivariateStatistic

public class Skewness extends AbstractStorelessUnivariateStatistic implements Serializable
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 Mean and std is the 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) $
See Also:
  • Field Details

    • moment

      protected ThirdMoment moment
      Third moment on which this statistic is based
    • incMoment

      protected boolean incMoment
      Determines whether or not this statistic can be incremented or cleared.

      Statistics based on (constructed from) external moments cannot be incremented or cleared.

  • Constructor Details

    • Skewness

      public Skewness()
      Constructs a Skewness
    • Skewness

      public Skewness(ThirdMoment m3)
      Constructs a Skewness with an external moment
      Parameters:
      m3 - external moment
    • Skewness

      public Skewness(Skewness original)
      Copy constructor, creates a new Skewness identical to the original
      Parameters:
      original - the Skewness instance to copy
  • Method Details