/** * Access the degrees of freedom. * @return the degrees of freedom. */ public double getDegreesOfFreedom() { return getGamma().getAlpha() * 2.0; }
/** * For this disbution, X, this method returns P(X < x). * @param x the value at which the CDF is evaluated. * @return CDF for this distribution. * @throws MathException if the cumulative probability can not be * computed due to convergence or other numerical errors. */ public double cumulativeProbability(double x) throws MathException { return getGamma().cumulativeProbability(x); }
/** * Modify the degrees of freedom. * @param degreesOfFreedom the new degrees of freedom. */ public void setDegreesOfFreedom(double degreesOfFreedom) { getGamma().setAlpha(degreesOfFreedom / 2.0); }
/** * Access the domain value lower bound, based on <code>p</code>, used to * bracket a CDF root. This method is used by * {@link #inverseCumulativeProbability(double)} to find critical values. * * @param p the desired probability for the critical value * @return domain value lower bound, i.e. * P(X < <i>lower bound</i>) < <code>p</code> */ protected double getDomainLowerBound(double p) { return Double.MIN_VALUE * getGamma().getBeta(); }