StatisticsUtilities { public static double median(double[] xs) { Arrays.sort(xs); if (xs.length % 2 == 0) { return (xs[(xs.length / 2) - 1] + xs[xs.length / 2]) / 2.0; } else { return xs[xs.length / 2]; } }  static double percentile(final double[] values, final double p); static double median(double[] xs); static int argmax(double[] xs); static int argmax(int[] xs); @SuppressWarnings("unchecked") static int argmax(int[] xs, int rank); static int argmin(double[] xs); static int argmin(int[] xs); static int softmax(double[] ps, double temperature); static int probabilistic(double[] ps); static double[] distribution(double[] raw); static double[] distribution(int[] raw); static double mode(double[] xs); static double mode(double[] xs, double epsilon); static double maximum(double[] xs); static int maximum(Collection<Integer> xs); static long maximum(long[] xs); static double minimum(double[] xs); static double average(double[] xs); static int sum(int[] vals); static double sum(double[] vals); static int sum(Collection<Integer> xs); static double sumDouble(Collection<Double> xs); static double populationStandardDeviation(double[] xs); static double sampleStandardDeviation(double[] xs); static double populationVariance(double[] xs); static double sampleVariance(double[] xs); static double sumOfSquares(double[] xs); static double instantaneousErrorEnergy(double desired, double output); static double instantaneousTotalErrorEnergy(ArrayList<Pair<Double, Double>> pairs); static double averageSquaredErrorEnergy(ArrayList<ArrayList<Pair<Double, Double>>> samples); static double tValue(int runs);  }
@Test public void testMedian() { double[] test1 = { 1, 2, 3 }; double[] test2 = { 1, 50, 100 }; double[] test3 = { 1, 1, 100, 50 }; double[] test4 = { 1, 1, 1, 1 }; assertEquals(StatisticsUtilities.median(test1), 2.0, ERROR); assertEquals(StatisticsUtilities.median(test2), 50.0, ERROR); assertEquals(StatisticsUtilities.median(test3), 51 / 2.0, ERROR); assertEquals(StatisticsUtilities.median(test4), 1.0, ERROR); }