| From: | Martin Mueller <martinmueller(at)northwestern(dot)edu> |
|---|---|
| To: | "pgsql-general(at)lists(dot)postgresql(dot)org" <pgsql-general(at)lists(dot)postgresql(dot)org> |
| Cc: | "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | computing z-scores |
| Date: | 2018-05-24 15:15:59 |
| Message-ID: | 2CC1AFF5-BB3A-499D-8969-C5B3388ED534@northwestern.edu |
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| Lists: | pgsql-general pgsql-hackers |
You construct a z-score for a set of values by subtracting the average from the value and dividing the result by the standard deviation. I know how to do this in a two-step procedure. First, I compute the average and standard deviation. In a second run I use the formula and apply it to each value.
Is there a way of doing this in a single-step procedure or can you chain the two parts together in one query? This goes beyond my SQL competence.
Martin Mueller
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