[issue40290] Add z_score to statistics.NormalDist

Change by Raymond Hettinger : -- keywords: +patch pull_requests: +18893 stage: -> patch review pull_request: https://github.com/python/cpython/pull/19547 ___ Python tracker __

[issue40290] Add z_score to statistics.NormalDist

New submission from Raymond Hettinger : I've had a couple of requests for a z-score method, once to produce an actual z-score for output and another as a way of normalizing gaussian inputs for machine learning. Proposed: >>> iq = NormalDist(100, 15) >>> iq.zscore(142) 2.8 Same r