### Question:
MeanAndStandardDeviation implements Serializable { @Override public boolean equals(Object obj) { if (obj == this) { return true; } if (!(obj instanceof MeanAndStandardDeviation)) { return false; } MeanAndStandardDeviation that = (MeanAndStandardDeviation) obj; if (!ObjectUtils.equal(this.mean, that.mean)) { return false; } if (!ObjectUtils.equal( this.standardDeviation, that.standardDeviation) ) { return false; } return true; } MeanAndStandardDeviation(double mean, double standardDeviation);  MeanAndStandardDeviation(Number mean, Number standardDeviation); Number getMean(); double getMeanValue(); Number getStandardDeviation(); double getStandardDeviationValue(); @Override boolean equals(Object obj); @Override String toString();  }### Answer:
@Test public void testEquals() { MeanAndStandardDeviation m1 = new MeanAndStandardDeviation(1.2, 3.4); MeanAndStandardDeviation m2 = new MeanAndStandardDeviation(1.2, 3.4); assertEquals(m1, m2); assertEquals(m2, m1); m1 = new MeanAndStandardDeviation(1.0, 3.4); assertFalse(m1.equals(m2)); m2 = new MeanAndStandardDeviation(1.0, 3.4); assertEquals(m1, m2); m1 = new MeanAndStandardDeviation(1.0, 3.0); assertFalse(m1.equals(m2)); m2 = new MeanAndStandardDeviation(1.0, 3.0); assertEquals(m1, m2); }