### Question:
Statistics implements Serializable { public double standardDeviation() { assertDataPresent(); return Math.sqrt(variance()); } private  Statistics();  Statistics(final double... values);  Statistics(final Collection<? extends Number> collection);  Statistics(final Statistics statistics); double max(); double min(); long count(); double sum(); double average(); double variance(); double standardDeviation(); static final Statistics EMPTY; }### Answer:
@Test public void shouldGiveTheStandardDeiviation() { assertEquals(standardDeviation(values), stats.standardDeviation(), 1E-8); }