def test_pearson_correlation(self):
rows = (
(-1, 0, 'a'),
(0, 0, 'b'),
(1, 3, 'c')
)
table = Table(rows, self.columns)
self.assertEqual(table.pearson_correlation('one', 'one'), Decimal('1'))
self.assertAlmostEqual(table.pearson_correlation('one', 'two'), Decimal('3').sqrt() * Decimal('0.5'))
def test_pearson_correlation_zero(self):
rows = (
(-1, 3, 'a'),
(0, 3, 'b'),
(1, 3, 'c')
)
table = Table(rows, self.columns)
self.assertEqual(table.pearson_correlation('one', 'two'), Decimal('0'))
