URI: http://www.uncertml.org/distributions/chi-square ChiSquareDistribution N/A A random variable $$x$$ is Chi-square distributed if the probability density function (pdf) is of the form shown below. The distribution is usually denoted as $$x \sim \mathcal{X}_\nu$$ where $$\nu$$ is known as the degrees of freedom (d.f) parameter. The d.f. has to be positive and $$x$$ has to be non-negative for the density to be defined. The Chi-square distribution is a special case of the Gamma distribution where $$X \sim Gamma(k=\nu/2, \theta=2)$$. $$\nu$$ (degreesOfFreedom) a positive integer $$x$$ a positive real $$f(x; \nu) = \frac{1}{\Gamma(\nu/2) 2^{\nu/2}} x^{\nu/2-1} exp(-x/2)$$ http://en.wikipedia.org/wiki/Chi-square_distribution continuous variables, distribution http://mathworld.wolfram.com/Chi-SquaredDistribution.html    1 1 2 3  // Single value {"ChiSquareDistribution":{"degreesOfFreedom":[1]}} // Multiple values {"ChiSquareDistribution":{"degreesOfFreedom":[1,2,3]}}  // Single value declaration ChiSquareDistribution csd = new ChiSquareDistribution(1); // Multiple value declaration ChiSquareDistribution csd = new ChiSquareDistribution(new int[] {1, 2, 3}); // Parsing from an XML file XMLParser xml = new XMLParser(); ChiSquareDistribution csd = (ChiSquareDistribution)xml.parse(new File("chi-square-distribution.xml")); // Parsing from a JSON file JSONParser json = new JSONParser(); ChiSquareDistribution csd = (ChiSquareDistribution)json.parse(new File("chi-square-distribution.json")); // Encoding to an XML file XMLEncoder xEncoder = new XMLEncoder(); xEncoder.encode(csd, new File("chi-square-distribution.xml")); // Encoding to a JSON file JSONEncoder jEncoder = new JSONEncoder(); jEncoder.encode(csd, new File("chi-square-distribution.json"));