### Question:
App { public static double std(List<Double> numbers, double mean) { double sumSquare = 0; for (double f : numbers) { double diff = f - mean; sumSquare += diff * diff; } return Math.sqrt(sumSquare / 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 zeroStd() { List<Double> zeroes = Arrays.asList(0d,0d,0d,0d); double std = App.std(zeroes, 0); assertEquals(0, std, 0); }