Variation on a theme?

[Merry]

I've just read a BBC news article about the aging population of Christchurch, Dorset (near where I live).

One sentence attracted my attention:

"A century ago, the median age of the entire country was only 25."

Median - doesn't that mean the middle value in a list of numbers, not the average? So if you had 1, 8, 30, 1000 and 5000 the median would be 30 but the average (mean?) would be 1+8+30+1000+5000 divided by 5 = approx. 1207.

So, what did they mean in the article? Surely they didn't mean life expectancy as most journalists say 40 for that, even in Victorian times.

They can't have meant median (can they?) because wouldn't that mean no one lived to more than 50? If they meant the average age of the population we could see how true that is by looking at the 1911 census.....

Discuss.

[kiterunner]

Median is the middle value in the list, as you said, yes but that doesn't mean that nobody lived to more than 50.

[Merry]

How would the list work then?

Oh, I see - line everyone up in order of age and you would have so many million people in the line. Find the middle person and they would be aged 25 (in 1914)?

Is that it?

I wonder if 25 is correct? (I do have better things to do really lol)

[kiterunner]

How would the list work then?

Oh, I see - line everyone up in order of age and you would have so many million people in the line. Find the middle person and they would be aged 25 (in 1914)?

Is that it?
Yes, that's right.

I wonder if 25 is correct? (I do have better things to do really lol)

I don't know.

[Phoenix]

I know that health authorities use median in some of their calculations. As Merry has demonstrated, the median figure is pretty meaningless when only a few items are included.

If you have a huge mass of people, then the median (for females at least) would have to be within the child-bearing range for a population to continue to grow. (If you assume a static situation with no migration!)

Did the article say what the latest calulated median was?

I would imagine that median is a much better representative as a long tail of people over (say) 80 would weight the figures unduly (as Merry has also demonstrated!)

(Typing this as I go off to work - needs revision, but you hopefully know what I mean!)

[Merry]

Looks like it's right - This is just England, as an example (figures from ancestry):

16,386,614 aged under 25

599,624 aged 25

16,340,875 over 25

So the middle person would be 25.

The median age in Christchurch (according to the article) is a few months short of 70 years! Shocking!

[Merry]

Did the article say what the latest calculated median was?


Only for a few aged places:

Christchurch 69.8 years

Eastbourne 71.1 years (that's top)

I don't know if these are new figures or where they came from.

[JBee]

However many more people retire to the coast and Eastbourne is one of the more popular places.

[Merry]

However many more people retire to the coast and Eastbourne is one of the more popular places.


Eastbourne 1911:

23,660 under 25

1030 aged 25

25,198 aged over 25

So, in 1911 Eastbourne was similar to country as a whole.

[WendyPusey]

Looks as if they missed the Isle of Wight out!

We have loads of retired elderly people living here, so I thought we would have been on that list somewhere.

[Merry]

You would think so, wouldn't you, but the 2011 census demographics states:

The average age of people in Isle of Wight is 44, while the median age is higher at 46.

[Janet]

Yes, agree, I think a median age of 25 is just another way of saying that half the population is under 25 and the other half is over 25. Half the people by you are 70+ Merry?!? Those are some interesting numbers. Not even some of our Florida and Arizona counties are that high.

[Merry]

Half the people by you are 70+ Merry?!?

Just about, Janet!

[anne fraser]

I read somewhere that the median age for England has just passed 40 for the first time ever. I think it is partly due to aging baby boomers and that it is expected to drop back below 40 some time this decade.