def test_t_two_sample_switch(self):
"""t_two_sample should call t_one_observation if 1 item in sample."""
sample = Numbers([4.02, 3.88, 3.34, 3.87, 3.18])
x = Numbers([3.02])
self.assertFloatEqual(t_two_sample(x, sample), (-1.5637254, 0.1929248))
self.assertFloatEqual(t_two_sample(sample, x), (-1.5637254, 0.1929248))
# can't do the test if both samples have single item
self.assertEqual(t_two_sample(x, x), (None, None))
def test_t_two_sample_no_variance(self):
"""t_two_sample should return None if lists are invariant"""
x = Numbers([1, 1, 1])
y = Numbers([0, 0, 0])
self.assertEqual(t_two_sample(x, x), (None, None))
self.assertEqual(t_two_sample(x, y), (None, None))
def test_t_two_sample(self):
"""t_two_sample should match example on p.225 of Sokal and Rohlf"""
I = Numbers([7.2, 7.1, 9.1, 7.2, 7.3, 7.2, 7.5])
II = Numbers([8.8, 7.5, 7.7, 7.6, 7.4, 6.7, 7.2])
self.assertFloatEqual(t_two_sample(I, II), (-0.1184, 0.45385 * 2), 0.001)
