@Test
public void testGetMAD() {

    double[] list = new double[]{1, 6, 3, 7, 11};
    assertEquals(3, PpeOp.getMAD(list), 1e-10);
    double[] list2 = new double[]{0, 0, 3, 1, 11};
    assertEquals(2, PpeOp.getMAD(list2), 1e-10);
    double[] list3 = new double[]{8, 0, 103, 20, 21};
    assertEquals(6.5, PpeOp.getMAD(list3), 1e-10);
}