### Question:
App { public static double mean(List<Double> numbers) { double sum = 0; for (double f : numbers) { sum += f; } return sum / numbers.size(); }  static void main(String[] args); static List<Double> compute(); static List<Double> loadFromFile(String filepath); static double mean(List<Double> numbers); static double std(List<Double> numbers, double mean); static List<Double> normalize(List<Double> numbers, double mean, double std); static void writeToFile(List<Double> numbers);  }### Answer:
@Test public void meanWithNegatives() { List<Double> numbers = Arrays.asList(-1d,1d); double mean = App.mean(numbers); assertEquals(0, mean, 0); }
@Test public void zeroMean() { List<Double> zeroes = Arrays.asList(0d,0d,0d,0d); double mean = App.mean(zeroes); assertEquals(0, mean, 0); }