# What can we do about the “What kind of distribution is this?” questions?

There are many questions with near identical names about 'recognizing a distribution', for example:

These seemingly identical questions clutter the related questions while they are often unrelated searches:

• Recognizing a potential distribution from a plot;
• Recognizing a potential distribution from just a text description of a process;

Hence the 'related questions' may not help future visitors searching for either of these three, nor does using the search bar. Should we perhaps adopt a distinct way to name these kinds of questions, or flag them duplicate with some reference to canonical answer(s)?

• +1 I believe this ambiguity and lack of good possibilities to classify/order/simplify questions/problems from a rather broad type is part of the difficulty with efficiently finding/answering questions on CV. – Sextus Empiricus Aug 17 '18 at 10:30
• Perhaps a tag like distribution-identification might be useful? – Stephan Kolassa Aug 17 '18 at 16:38
• @MartijnWeterings, thanks for fixing some already. I have tagged all of these under distribution-identification and will think of a decent description of the tag. – Frans Rodenburg Aug 20 '18 at 6:55

I don't think a canonical answer is possible here.

That's just a case when more specific & descriptive titles are needed. If it's about a formula, it can be put into the title, e.g.:

What distribution has density proportional to $(x-1) \theta^2 (1-\theta)^{x-2}$?

If it's about a plot, then I'd try to provide some description of the plot in the title:

What is this right-skewed distribution over non-negative values?

What is this weird-looking bimodal distribution (sea-level measurements)?

etc.

BTW, the last question I asked falls exactly into this category of questions:

How is the family of distributions with PDF proportional to $(1+ax^2)^{-1/a}$ called?

• (+1) What about if there were a question+answer that described the properties of the most commonly encountered distributions? Wouldn't that allow us to close many of these as duplicates? – mkt Aug 17 '18 at 12:13
• @mkt I don't know. Perhaps. But it would require a lot of work to do it well. – amoeba Aug 17 '18 at 14:42
• @mkt: I wonder whether that kind of encompassing answer would be a good fit to CV. Perhaps a list of potential resources might be helpful, like the NIST/SEMATECH Gallery of Distributions, or Wikipedia's list of common distributions, or a few standard textbooks. – Stephan Kolassa Aug 17 '18 at 16:37
• @amoeba Agreed, it would be. – mkt Aug 17 '18 at 17:01
• @StephanKolassa I'm not sure either. It's a kludgy workaround that lets us close a bunch of unhelpful questions, and is perhaps not worth it. I do like your tag suggestion. – mkt Aug 17 '18 at 17:02
• Thanks @amoeba, I think changing the titles to include the category would already be a big improvement. So is it okay if I edit the example questions' titles, or should I leave that to a moderator so I don't bump all of these questions? – Frans Rodenburg Aug 20 '18 at 4:44
• @FransRodenburg Mods cannot edit anything without bumping either. So I'd say you can go ahead. Thanks. – amoeba Aug 20 '18 at 6:28