def test_zscore_means_to_zero():
x = [1, 2, 3, 4, 5, 6, 3, 2, 4, 5, 3, 2, 3, 4]
out = stats.z_score(x)
assert abs(out.mean() - 0) < 1e-6
def test_zscore_sd_to_1():
x = [1, 2, 3, 4, 5, 6, 3, 2, 4, 5, 3, 2, 3, 4]
out = stats.z_score(x)
assert abs(out.std() - 1) < 1e-6
def test_zscore_returns_same_size():
x = [1, 2, 3, 4, 5]
out = stats.z_score(x)
assert len(x) == len(out)