Mnemonic for platykurtic and leptokurtic

Question

I keep confusing terms leptokurtic and platykurtic. Is there a good mnemonic to help remember which is which?

"Lepto" means "little", "platy" means "flat", and both are equally unrelated to thickness of a tail. It also does not help that "lepto" (small) means excess positive kurtosis (had to look it up, btw. Again.)

@Prometheus, so if tails of a distribution are kind of its feet, left and right, then flat feet means not too much of distribution is there, something like that? — nsg, Nov 03 '13 at 04:49

bof · Answer 1 · 2013-11-03T02:51:09.280

2

You only need a mnemonic for one of them, right? For "platy-" think of a plain or plateau or platyhelminthes or platypus or platter. Or just think of the word flat--which sounds more like "flat" to you, platy or lepto?

edited Nov 03 '13 at 02:51

answered Nov 03 '13 at 02:44

bof

6,376

my difficulty is that "lepto" is "little" and "platy" is "flat" and they are pretty much same thing in my mind – nsg Nov 03 '13 at 02:58
little sucks, i mean when have you heard little is good, flat however is awesome. – Asinomás Nov 03 '13 at 03:01
Well, try to think of them as "slender" and "broad", or "thin" and "fat". – bof Nov 03 '13 at 04:04
leptos doesn't mean "little". It's "thin, skinny, thin". A tall skinny person is leptos. – Zavosh Nov 03 '13 at 06:21

score 0 · Answer 2 · answered Aug 06 '17 at 21:58

0

I know this question is a few years old, but one I've come up with (not sure if original) is that a leptokurtic distribution has a big "peak" to lepto (leap over) and that a platykurtic distribution is a plateau and thus nothing or is something very small to jump over.

Yeah, it's dumb, but it works.

answered Aug 06 '17 at 21:58

Ahmad Ragab

109

Why the downvote? – Ahmad Ragab Aug 06 '17 at 22:12
While "lepto" means positive excess kurtosis, it does not imply "high peak." The peak could be flat, bimodal, sinusoidal, anything at all: take a distribution with any shape peak whatsoever, and mix it with a much wider distribution with small mixing p, and the resulting distribution will have the same shape of peak as the original, but very high kurtosis. Similarly, "platy" means negative excess kurtosis, but does not imply flat-topped or lowly-peaked. The beta(.5,1) distribution, has negative excess kurtosis but an infinite peak. Kurtosis measures outlier potential, not the peak. – BigBendRegion Oct 25 '17 at 22:43
You can have flat-topped distributions with very high kurtosis as easily as peaked ones, and you can have peaked distributions with very low kurtosis as easily as flat-topped ones. See https://stats.stackexchange.com/q/659400/102879 – BigBendRegion Feb 13 '25 at 16:58

mcint · Answer 3 · 2025-01-31T09:45:59.153

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The meaning of platykurtic, from platy-, misread this as plate-y, and remember that the described distribution has a limited and circumscribed, focused, tendency.

It’s worth recalling and associating mesokurtic, with meso- meaning “middle”, Greek all, having 0 excess kurtosis.

By contrast, in leptokurtic distributions, lepto-, samples leap out (enhancing kurtosis).

Wikipedia cites both -kurtic and -kurtotic

Glad this question was here, I was struggling with this myself, and glad there were other answers here that gave some thought to this, and I could build on. And I’m glad this question is here still, SO Q norms being what they are, at least on other SO sites.

edited Jan 31 '25 at 09:45

answered Jan 31 '25 at 09:37

mcint

101

Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center. – Community Jan 31 '25 at 09:38

Mnemonic for platykurtic and leptokurtic

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