I often forget it, so I quote it from scipy.org and make a note.

```
>>> import numpy as np
>>> from scipy import stats
>>> a = np.array([ 0.7972, 0.0767, 0.4383, 0.7866, 0.8091, 0.1954,
0.6307, 0.6599, 0.1065, 0.0508])
>>> stats.zscore(a)
array([ 1.1273, -1.247 , -0.0552, 1.0923, 1.1664, -0.8559, 0.5786,
0.6748, -1.1488, -1.3324])
>>> b = np.array([[ 0.3148, 0.0478, 0.6243, 0.4608],
[ 0.7149, 0.0775, 0.6072, 0.9656],
[ 0.6341, 0.1403, 0.9759, 0.4064],
[ 0.5918, 0.6948, 0.904 , 0.3721],
[ 0.0921, 0.2481, 0.1188, 0.1366]])
>>> z_score = stats.zscore(b, axis=1, ddof=1)
>>> z_score
array([[-0.19264823, -1.28415119, 1.07259584, 0.40420358],
[ 0.33048416, -1.37380874, 0.04251374, 1.00081084],
[ 0.26796377, -1.12598418, 1.23283094, -0.37481053],
[-0.22095197, 0.24468594, 1.19042819, -1.21416216],
[-0.82780366, 1.4457416 , -0.43867764, -0.1792603 ]])
>>> np.allclose(np.mean(z_score, axis=1), np.zeros(5))
True
```

Reference (quote) scipy.org

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