### Question:
ChiSquaredDistribution extends AbstractContinuousDistribution { public double getDegreesOfFreedom() { return gamma.getShape() * 2; } ChiSquaredDistribution(double degreesOfFreedom); double getDegreesOfFreedom(); @Override double density(double x); @Override double logDensity(double x); @Override double cumulativeProbability(double x); @Override double getMean(); @Override double getVariance(); @Override double getSupportLowerBound(); @Override double getSupportUpperBound(); @Override boolean isSupportConnected(); @Override ContinuousDistribution.Sampler createSampler(final UniformRandomProvider rng);  }### Answer:
@Test void testParameterAccessors() { final ChiSquaredDistribution distribution = makeDistribution(); Assertions.assertEquals(5d, distribution.getDegreesOfFreedom()); }