# On average every 1.3rd or 1.3th something?

• On average every 1.1st or 1.1th something?
• On average every 1.2nd or 1.2th something?
• On average every 1.3rd or 1.3th something?

What is the correct formulation for a decimal ordinal number?

Hah! I knew I would find it sooner or later!

I would simply avoid the use of ordinals that are not whole numbers. They make no sense, and they can easily be avoided.

If there is a line of people, I cannot say that I pick every 1.5th person.

Every suggests you actually identify an individual occurrence of something, which can never be the 1.1st occurrence.

Change the phrase to something like

10 out of 11 (for 1.1)
10 out of 13 (for 1.3)
2 out of 3 (for 1.5)

• well, that's not exactly an answer. an answer might be "there is no way to express this - not even in colloquial language." – Raffael Jun 2 '14 at 17:42
• @Raffael: If it makes it clearer, I will rephrase what I wrote: "Ordinals that are not whole number make no sense and should not be used." Since they make no sense, there is no "this" in "there is no way to express this". – oerkelens Jun 2 '14 at 17:52
• you really think that a language can only express what makes sense? Wittgenstein would have been a happier man with more time for parties and friends ... – Raffael Jun 2 '14 at 17:58
• @Raffael No, I do not think that. However, if you want to convey a meaning to "every 1.1st item", you should definitely explain what that meaning is, as the meaning is not obvious. At least Wittgenstein gave it a try - although his success is debatable :P – oerkelens Jun 2 '14 at 18:05
• it's a completely intuitive concept - like a "hot nerd" is a "herd" ... – Raffael Jun 2 '14 at 18:07

Googling for "0.3th quantile" and "0.3rd quantile" reveals that both options are used in scientific literature.

• Doesn't mean they're both right.... ;) – Shokhet Jun 25 '14 at 20:16