The Scale of Things

[prefectmarcus]

No: HPFGUIDX 43310

--- In HPforGrownups at y..., "rosie" <crana at n...> wrote:
> Hi Marcus, just been reading your post:
> 
> "I got the ratios from my own experience with schools versus 
> populations.  There were 350 in a grade in my HS from a population 
of 
> 7000.  In another town where I lived, there were 120 kids per grade 
> in a population of 2400.  So the 20:1 ratio is pretty consistent."
> 
> and
> 
> "In today's culture, there are about 200 people in the population 
for every 1 
> student in a given year.  Now assuming that wizards live twice as 
> long as muggles, make that 400 to 1."
>   
> Ok, I'm not trying to be funny here but I don't really get this, 
I'm sorry. Are you using 20:1 (40:1) or 200:1 (400:1)?
> 
> Also... using data from the year 2000.
> 
> Total population of Britain: 59,755,700
> Number of children aged 10 - 15 exclusive: 4,598,000 million 
> 
> That is 5 years at school, giving approximately 919600 children per 
year in secondary school in Britain. 
> 
> Using the figure of 150/year at Hogwarts, that would give an 
approximate ratio of 6130:1 muggle:Hogwarts children - a tiny 
minority.
> 
> Then looking at the ratio of secondary pupils to adults:
> 
> In 2000, there were 12.1 million children aged under 16. Taking 
this away from the total population leaves the adult population at 
47.6557 million. 
> 
> So the ratio of secondary pupil : adult is 1: 10.4 (3 sig figures). 
This is quite a way from either the 1:20 or 1:200 you suggested. 
> However, if we then double it as you suggested to account for 
wizard lifespans, we do have a 1:20 secondary pupil: adult ratio.
> 
> Taking this straight from the Hogwarts figure given by JKR (1000 
Hogwarts students), that would be 1000 x 20, to give an adult wizard 
population of around 20,000. So around 2950 Muggles : 1 magical 
person.
> 
> Okay, anyone can criticise my maths if they think I have it wrong 
as I'm no hot shakes at maths. Anyone who wants to find interesting 
UK statistics can at http://www.statistics.gov.uk/ . 
> 
> Rosie
> 
> 
> 
> 
> [Non-text portions of this message have been removed]

Total population of Britain: 59,755,700
Number of children aged 10 - 15 exclusive: 4,598,000 million 

Let's simplify things.
60Million Britains
4.5Million Schoolkids divided into six years = 750,000 kids per year

Ratio of 60Million Pop to 750,000 kids in a year = 80:1

Double that for longer-lived Wizards = 160:1

Using 1000 kids in 7 years (approx 150/yr) works out to total Wizard 
population in Great Britain of 24,000.

Using 40 kids per year works out to a total Wizard pop of 6400.

60,000,000 to 24,000 is 2500:1 Gen pop to Wizards. (Large Hogwarts) 
60,000,000 to  6,400 is 9375:1 Gen pop to Wizards. (Small Hogwarts)

No matter how you slice or dice it, there are not very many wizards 
per general population.  But even the 6400 number could easily 
support Diagon Alley.  I grew up in a town that big and our 
commercial center would have swamped Diagon Alley.


Mark