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Is there a standard symbol for percentile in mathematics, much like % is used for percentage? I have trying to get the right answer but only getting conflicting answers and logic.

Brian White
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Karthikeyan
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  • What do you mean "does it exist"? – 5xum Feb 29 '16 at 15:23
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    It is generally written as $P_i$ where $i$ is the percentile. – Neil Feb 29 '16 at 15:24
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    Perhaps the point of confusion would be clearer if you showed what you had found, even the things that don't make sense to you--in fact, it may be especially important to know exactly what things don't make sense to you. – David K Feb 29 '16 at 15:28
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    @DavidK This is a notation question. The asker is looking to find the one symbol used for denoting percentiles, should a unique symbol exist for it. Finding more than one symbol seems to be the part that doesn't make sense to them, being that there's apparently more than one unique symbol. Them summarizing their previous findings shouldn't affect the answer to this question. – Axoren Feb 29 '16 at 15:51
  • It would be helpful to be a little clearer as to what you are trying to do with this symbol. To me, the obvious answer is "%". But that is so obvious, I doubt that this is what you are after. – Paul Sinclair Feb 29 '16 at 17:55
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    @Axoren The question says OP already found answers, but they were unsatisfactory. Why attempt an answer when it seems likely that the answer will duplicate something OP saw elsewhere and that repeating that answer will not help? – David K Feb 29 '16 at 18:31
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    @DavidK There's a double edge to this. Yours is the first edge. If he provides the answers already gotten, it invites answers which simply "pick one" and don't provide evidence or other persuasion for the answer. Thus making this question another source of "conflicting answers". – Axoren Feb 29 '16 at 18:40
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    @Axoren An answer like the one you described would be a low-quality answer to any question--and it is just as likely to be made to the question as originally asked. A good answer takes more effort. I'm suggesting that if someone wants people to put that much effort into answers, they should be willing to put effort into questions. You and the OP are free to ignore this opinion--it's only one person's opinion, after all--but if you like, you can ask in Meta and see if there is a consensus there about whether the question would be better or worse if previous findings were included. – David K Feb 29 '16 at 18:54
  • A good indication that there is no special symbol (apart from $P_{nn}$), is that the Unicode character set doesn't define one. –  Oct 11 '17 at 07:46

3 Answers3

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As Neil mentions in his comment $P_i$ is a common notation to denote the $i$-th percentile.

The Wikipedia page on Percentile doesn't actually mention the notation as far as I can see but denotes quartiles as $Q_1$, $Q_2$, and $Q_3$ several times and from this it's logical that percentiles would be denoted by $P_i$ (and likewise other quantiles with their respective character in the same way).

A real world example of this notation (even if it's not subscript) is how you request percentiles in the Amazon CloudWatch API which follows the pattern p(\d{1,2}(\.\d{0,2})?|100) - or p5 for the 5th percentile, p70 for the 70th percentile, p50.36 for the 50.36th percentile, and p100 for the maximum value.

Raniz
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If you want to specify the vector (i.e. vector C) and the percentile (i.e. 95), then you may write: percentile(C,95).

Candace Agonafir
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If you want an LLM to understand say the 12.34th percentile without having to give it special instructions, you can write it as P12.34th%. In contrast, writing it merely as P12.34% (without "th") is ambiguous to the LLM since it can be misunderstood for probability or proportion or percentage.

Asclepius
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