Human Height is not Bimodal

[atoo]

This is a bit of a niche topic I know, but I thought it might be interesting to at least some people.

If there's a scalar characteristic which has a different mean in men and in women, then the distribution for the whole adult population will be Bimodal if the difference in the means is large compared to the variation within each sex.

This is the case for example in gamete size or testosterone levels. But it is not the case for height - the difference between the average man and average woman is less that the difference within each sex. So human height is not in fact a bimodal distribution. It's just a bit flatter than a bell curve (image attached).

Much more detail in this paper: https://faculty.washington.edu/tamre/IsHumanHeightBimodal.pdf,.including why people often find bimodality in practice - e.g. small sample sizes, and men lying about their height.

Did anybody say it was? (Genuine question.) It would never have occurred to me to think it was; my subjective impression is that almost everything that differs between the sexes doesn't differ sharply enough to give a bimodal distribution.

Yes, it's very often used as an example of a bimodal distribution. There are many papers, textbooks, exam questions, and internet discussions that assume that it is bimodal - some citied in the paper I linked to.

From the intro to the paper: "The combined distribution of heights of men and women has
become the canonical illustration of bimodality when teaching introductory statistics."

''the difference between the average man and average woman is less that the difference within each sex.''

But thats just logical, isn't it? Given that people can range in height from 4 to 7 feet?

Translation, please.

I think they mean that there's as much difference in height within the group 'women' and 'men' as there is between women and men.
I think that's the long and the short of it

What's the point in this post?

The average man is taller than the average woman.

I don't get it.

Yeah, I'm wondering if we're supposed to go, 'oh, in that case it's obviously fine for men to use women's spaces.'

If it was a bimodal distribution the averages for men and women would be further apart and men-who-are-shorter-than-average would not overlap much with women-who-are-taller-than-average.

(But sex isn't one distribution with two peaks.)

gasp some women are taller than some men

<Needs a lie down>

I did introductory stats and make female height distributions never came up

the most normal thing to do would be to plot the two groups in different colours and see the difference in the mean and then run proper tests to see if the difference would be statistically significant

A man told me he was bleeding from his genitals recently. I told him to get to his GP stat but maybe I should just have given him a tampon? Should I have measured him first? Gosh it’s so hard to tell what the right thing to do is in these circumstances

Ah.....now I get it. Or do I? Maybe I'm paranoid.

I knew someone had done a chart of this that I liked!

Number of people is on the left vertical axis (Y axis).

Summary:

1. The tallest quarter of women are as tall as the shortest quarter of men.
2. The tallest tenth of men are as tall as the shortest tenth of NBA players.
3. The tallest one-hundredth of women are as tall as the shortest hundredth of NBA players.

Notes:

• "Quarter", "tenth" and "hundredth" are approximations;
• Most NBA players are men, this chart hasn't assumed they're a third sex
• ... but maybe OP would like to explore that point 😏

This is not new information.

So the pink lines and blue lines are more close to each other than more separate?

I believe that the OP might have been inspired by a male poster posting on the AMA thread that sex was bimodal.

And the good news is that entitled men will still be able to fit on the toilets in womens cubicles. Phew, thought for a minute there we might have to have them all raised up on blocks or something so those long male legs would be comfy.🤓

Indeed not, and that is in fact a bimodal distribution.

Genderists like to say human sex is bimodal. As far as I know, no-one has yet identified the sperg or the spegg gametes, so sex is binary.

Maybe binary now identifies as bimodal, leaving bimodal no choice but to identify as a blended distribution (or some other made-up identity)?

Have another of my favourite pictures :)

And the poster seemed to have read the paradox institute article I posted to explain why sex is binary and not bimodal and not grasped what the article was saying.

Plus the poster failed to grasp how humans don’t chart on an axis of more male to less male and more female to less female. I think they genuinely think some male people are more ‘male’ than others so that they believe the whole bimodal thing works….

here is the thread and the post at 17.23 and I think height was mentioned further along the discussion.

https://www.mumsnet.com/talk/womens_rights/5336462-tw-who-supports-the-sc-ruling-ama?page=5

But the OP (who is not the poster in question talking about sex being bimodal) didn’t want the thread derailed further so OP has done the right thing and not posted the clarification on the thread.

I would think this refutes the idea that the famous tall swimmer with big hands is why men are allowed in women’s toilets.

Height is not bimodal, so some women are tall doesn’t mean that sex is a spectrum.

and stuff.

the distribution for the whole adult population will be Bimodal if the difference in the means is large compared to the variation within each sex.
This is the case for example in gamete size or testosterone levels.

Gamete size is not bimodal. There is no distribution. Big or small - those are your options. And as well as the sizes being binary, they are totally different types of cell.

I don't understand the premise of the thread at all.

averagely tall women are about the same height as short men but shorter than averagely tall men.

tall women are about the same height as averagely tall men, but shorter than tall men.

etc etc etc

e.g. basketball is a sport that strongly favours tall players, but the extent of this varies strongly by position, eg freakish athleticism/skill is non-negotiable for point guards, height a huge bonus. for centres it's the other way round. most other positions are somewhere in-between.

here are the heights of the male and female** 2024 Olympic rosters.

male: 6'2", 6'3", 6'4", 6'4", 6'5", 6'5", 6'8", 6'9", 6'9", 6'9", 6'10", 7'0", average 6'9".

women: 5'9", 5'10", 5'11", 6'0", 6'1", 6'2", 6'3", 6'4", 6'4", 6'5", 6'6", 6'9", average 6'2".

'** it's unconfirmed but the tallest member of the women's team, Britney Griner, is likely a DSD male.

Tall women are not men.
Short men are not women.
HTH.

Exciting stuff.