Is there a standard for statistical symbols? Mathematics have ISO 80000-2:2019 which specifies mathematical symbols, explains their meanings, and gives verbal equivalents and applications. Is there an equivalent for statistical symbols?
Edit: the question is broader than the question of statistical model notation since it also encompasses simpler topics (such as the symbol for average, median, etc.)
 A: So I found out that there is a standard. See

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*ISO 3534-1:2006 Statistics — Vocabulary and symbols — Part 1: General statistical terms and terms used in probability

*ISO 3534-2:2006
Statistics — Vocabulary and symbols — Part 2: Applied statistics

*ISO 3534-3:2013 Statistics — Vocabulary and symbols — Part 3: Design of experiments

*ISO 3534-4:2014 Statistics — Vocabulary and symbols — Part 4: Survey sampling

A: According to the Oxford dictionary of statistical terms (and probably many other standard works) the term 'standard' has already been claimed by Karl Pearson in 1894.
Quote from Contributions to the mathematical theory of evolution (emphasis is mine)

In the case of a frequency-curve whose components are two normal curves
...
each component normal curve has three variables : (i.) the position of its axis, (ii.) its “standard-deviation” (Gauss’s “Mean Error”, Airy’s “Error of Mean Square“). and (iii.) its area.

So, No, there aren't standards in statistics except for standard deviations and standard errors.
We can blame professor Pearson for not contacting the International Standards Organization to discuss about standards in statistics (or as Crocefisso notes, not Pearson personally, but his spirit).
Apparently, as Kjetil notes, there has been a small resistance and the ISO has also been working on statistics in ISO-3534 Statistics — Vocabulary and symbols (I am not sure I am linking correctly since I am not buying these standards)
