Average Height Bias

[mklhawley]

Greetings all,

I commented upon the average height of males in Victorian London on a Tumblety thread, but I believe this issue is pertinent in many other areas. Considering averages can create an illusion of statistics, and then arguments can be based upon this illusion. For example, “Someone 6 feet 2 inches would stick out like a sore thumb, so they could not have been the elusive Jack the Ripper”. Let us assume that the average height of a male in Victorian London was 5 feet 8 inches. This does not mean that everyone was really close to 5 feet 8 inches. Plotting the heights of males creates a bell curve. Points:

1) This actually means 50% of the male population was taller than 5 feet 8 inches.

2) The bell curve data demonstrates that close to 15 % of the male population was taller than 6 feet! A person 7 feet tall would be outside of the bell curve so would stick out like a sore thumb. A person 6 feet 2 inches tall falls within the bell curve, so they would not.

3) Human perception - In my neck of the woods we have the Erie County fair. I am about an inch taller than today’s average height, but when I go to he fair, it seems that a much larger percentage of the males are taller than me. A killer 6 feet 2 inches tall would recognize that he is on the taller side but being around a population that tends to wear relatively large hats, I believe his height would not impede his desires.



What say you?

Sincerely,

Mike

[Marc]

1) This actually means 50% of the male population was taller than 5 feet 8 inches.

2) The bell curve data demonstrates that close to 15 % of the male population was taller than 6 feet! A person 7 feet tall would be outside of the bell curve so would stick out like a sore thumb. A person 6 feet 2 inches tall falls within the bell curve, so they would not.


What say you?

Hi Mike,

I'd say, if a mean figure of 5'8" is obtained with 50% of people taller than that, that could mean that the other 50% are smaller, then...nobody would measure 5'8" tall

I'm not very good at math, but I'd expect a fair majority of the said population (60% ?) to be at or very near to the mean figure, give or
take 1" or 1.5" at most.

Now, this is also, as you say, definitely a matter of perception

Just a few ideas to thrown in FWIW :

- if we talk about Whitechapel population, we mostly talk about hard working
people, engaged very young (8 to 10 ?) in daily, six days a week, manual labour, that is before normal growth is complete.

Moreover, many people living in the highly poluted and crowded area of the LVP East End didn't enjoy much sun light, nor probably a vitamin rich diet.
Perhaps I'm wrong, but I'd expect them to be, on average, slightly smaller than people living in other places and under better conditions.

- many people living in Whitechapel were from poor Eastern European backgrounds, and I wouldn't expect them to particularly tall, as a rule.

The above is purely conjectural, of course and your mileage may vary

[Rubyretro]

-

if we talk about Whitechapel population, we mostly talk about hard working
people, engaged very young (8 to 10 ?) in daily, six days a week, manual labour, that is before normal growth is complete.

I think that this is an excellent post, and I agree with nearly everything you say ( I'm sure that MJK was considered 'tall' because of her rural background).

I think that Garry pointed out the laws on compulsory schooling though -and maybe not so many children were in full time manual labour at that early age ?
(correct me if I'm wrong -infact I can count on everyone to do so !).

[belinda]

That is very interesting.

Under nourishment and disease such as Ricketts((sp) causing stunted growth.

Genetics are a factor too though.I am 5'2" the same height as most of the victims. My relatives on one side are all short.My grandmother was not even five foot nor were any of her sisters.

[Marc]

the laws on compulsory schooling though -and maybe not so many children were in full time manual labour at that early age ?
(correct me if I'm wrong

Hi Ruby,

IMHO, you're probably right and I was wrong, or at least, a bit pessimistic
Say 12 instead of 8 to 10 ?
Both my paternal Grand-Mother and her brother (respectively born in 1911 and 1914) went to school from 6 to 11, then were at work in a factory beginning at 12.
Interestingly, my paternal Grand-Father, from a rural background, didn't really 'work' before 16 or 17 years old.
Certainly, he helped with many farming task, but didn't work full day on a regular basis until his late teens.
On the maternal side, my Grand-Mother, born in 1914 too, went to school (which was then mandatory of course) but for a few months at a time only, and never really took on reading and writing so easily.
She also began to work in a factory at 12.

Based on the possible gap between 'mandatory' schooling and actual practice for the poorest/illiterate part of the Whitechapel population, and the economic realities of the East End in the 1880's, would 10 years old as the beginning age of an active career seem plausible ?

[protohistorian]

Greetings all,

I commented upon the average height of males in Victorian London on a Tumblety thread, but I believe this issue is pertinent in many other areas. Considering averages can create an illusion of statistics, and then arguments can be based upon this illusion. For example, “Someone 6 feet 2 inches would stick out like a sore thumb, so they could not have been the elusive Jack the Ripper”. Let us assume that the average height of a male in Victorian London was 5 feet 8 inches. This does not mean that everyone was really close to 5 feet 8 inches. Plotting the heights of males creates a bell curve. Points:

1) This actually means 50% of the male population was taller than 5 feet 8 inches.

2) The bell curve data demonstrates that close to 15 % of the male population was taller than 6 feet! A person 7 feet tall would be outside of the bell curve so would stick out like a sore thumb. A person 6 feet 2 inches tall falls within the bell curve, so they would not.

3) Human perception - In my neck of the woods we have the Erie County fair. I am about an inch taller than today’s average height, but when I go to he fair, it seems that a much larger percentage of the males are taller than me. A killer 6 feet 2 inches tall would recognize that he is on the taller side but being around a population that tends to wear relatively large hats, I believe his height would not impede his desires.

[ATTACH]9585[/ATTACH]

What say you?

Sincerely,

Mike

Hello Mike. Here is a dataset on stature that is independant of bias, being taken from skeletal remains. Dave

http://forum.casebook.org/showthread.php?t=3445&highlight=stature

[mklhawley]

Thanks Dave. Very interesting.

Mike

[Tom_Wescott]

Hi Mike and all,

I've heard the same flack since publishing my essay on Charles Le Grand - who was 6ft tall. I pointed out that 6ft tall Le Grand was also a criminal private investigator who regularly and successfully stalked and followed people without them seeing him. One occassion is well documented where he stalked and watched a policeman who's job it was to stalk and watch Le Grand! The officer had no idea that Le Grand was there.

So the long and short of it is that YES, a tall man could have been Jack the Ripper.

Yours truly,

Tom Wescott

[Marc]

JtR : incredible hulk or a midget ? ;-)

I've heard the same flack since publishing my essay on Charles Le Grand - who was 6ft tall. I pointed out that 6ft tall Le Grand was also a criminal private investigator who regularly and successfully stalked and followed people without them seeing him. One occassion is well documented where he stalked and watched a policeman who's job it was to stalk and watch Le Grand! The officer had no idea that Le Grand was there.

So the long and short of it is that YES, a tall man could have been Jack the Ripper.

Hi Tom,

With a name like his, Le Grand couldn't be a small guy

If the issue was to discuss whether a 6' tall guy would look like a giant among a 5'8" tall male population on average, the answer IMHO would probably be 'no'.
A 6' tall guy might be described as 'rather tall' by some other people, but they probably wouldn't pay to watch him shown in a cage across the streets.

On the other hand, if police or detective stalking is discussed, I'm not aware that especially taller people have a harder time not be remarked...as stalkers.
The needed trick for efficient stalking is to look like 'anyone else', and anyone else can be tall, or small, after all.
Unless you are 30% taller than others, wear a black cape, and brandish a indian knife over your head, efficient stalking has more to do IMHO with the distance you can keep from the individual you're stalking at, and the way you appear not to look at him/her, than with your standing height.

About JtR being 'tall', if 2" taller than average means 'tall' for you, yes he could have been 'tall', notwithstanding that light, distance, stance and body shape can duly distort anyone's take on an individual height, therefore 5'7" could perhaps be 6', or 5'3" for that matter.

Any more difference in height should mean, IMHO, that 'witnesses' were in serious need of a medical eyesight care among other things.
Otherwise, all 'witnesses' saw someone else that our killer, and then the real JtR could have been as tall as 7', or as small as 5'.

[mklhawley]

Hi Mike and all,

I've heard the same flack since publishing my essay on Charles Le Grand - who was 6ft tall. I pointed out that 6ft tall Le Grand was also a criminal private investigator who regularly and successfully stalked and followed people without them seeing him. One occassion is well documented where he stalked and watched a policeman who's job it was to stalk and watch Le Grand! The officer had no idea that Le Grand was there.

So the long and short of it is that YES, a tall man could have been Jack the Ripper.

Yours truly,

Tom Wescott

Hi Tom,

I posted a few articles on incidents with a "tall" suspect. Do they fit Le Grand as well?

Sincerely,

Mike

[mklhawley]

...I'm sorry. The articles are on the Tumblety thread.

[protohistorian]

taken from skeletal studies

These studies span more than 100 years. Dave

[joelhall]

If 50% of people were taller than the average height you wouldn't see a bell shaped graph. You would either see, if it were 50/50 two lines with a gap between, as the mean would record 0% indicence, or maybe even two bells either side of the mean; if height were evenly distributed, a straight line.

By its very definition, a normal distribution bell graph shows that the majority are close to the mean value, with those of average height being the largest group and each greater deviation from the mean has a lower incidence or group size as deviation increases, where the x axis represents deviation from the mean, and the y axis represents rate or incidence or group size.