public void ValidateInverseCumulativeDistribution(double d1, double d2, double x) { var n = new FisherSnedecor(d1, d2); double p = SpecialFunctions.BetaRegularized(d1 / 2.0, d2 / 2.0, d1 * x / (d2 + (x * d1))); Assert.That(n.InverseCumulativeDistribution(p), Is.EqualTo(x).Within(1e-8)); Assert.That(FisherSnedecor.InvCDF(d1, d2, p), Is.EqualTo(x).Within(1e-8)); }