StatisticsUtilities { public static double average(double[] xs) { double avg = 0; for (int i = 0; i < xs.length; i++) { assert!Double.isNaN(xs[i]) : "xs[" + i + "] is NaN!"; avg += (xs[i] - avg) / (i + 1); assert!Double.isNaN(avg) : "avg is NaN!"; } return avg; }  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 testAverage() { double[] test = {5, 9}; assertEquals(StatisticsUtilities.average(test), 7.0, ERROR); double[] test1 = {5, 5, 5, 5, 5, 5, 5, 5}; assertEquals(StatisticsUtilities.average(test1), 5.0, ERROR); double[] test2 = {0, 0}; assertEquals(StatisticsUtilities.average(test2), 0.0, ERROR); double[] test3 = {0, 1}; assertEquals(StatisticsUtilities.average(test3), 0.5, ERROR); double[] test4 = {0.1, 1.5, 3.5, 2.5}; assertEquals(StatisticsUtilities.average(test4), 1.9, ERROR); }