Interesting Non Poker Thinking Problem

[irchans]

Can you post the years for the other ages?

[CK1]

Looks like the correct answer is 110 based on the available data. There is no point arguing about it.

However, I want to point out a subtle thing that most of you missed. One can only get a lower bound for the correct answer by the arguments given so far. Let me clarify this. Let us assume that the oldest person alive is 115. So any answer that is much lower than 115 must be wrong. However the life expectancy can be a slowly varying function of age, and in the extreme case may approach a finite value. In which case, the correct answer can be much larger than the age of the oldest person alive. For example, the life expectancy in principle could level off at 2 years, in which case we would not know if there is a correct answer for this problem. Or if the question was posed differently, instead of year, if David had asked at what age you would have a life expectancy of 1 month, again there would not be a correct answer to the question.

There is a branch of engineering called reliability engineering where people analyze such thins as the lifetime of a transistor, which is important to predict how long your computer will last. In most cases the lifetime of products do level off at a finite value.

CK

[PseudoPserious]

I took a swag at the number of really old people in the US by basing it on how often they announce 105+ birthdays on morning, but I guess I lowballed it a tad.

On another note, there's an actuarial table called the "Life Table" that addresses this question. Here's the table that the SSA uses:

http://www.ssa.gov/OACT/STATS/table4c6.html

According to this data, the first age with >50% death probability is 106 for males and 108 for females.

PP

[Position]

[ QUOTE ]
One can only get a lower bound for the correct answer by the arguments given so far. Let me clarify this. Let us assume that the oldest person alive is 115. So any answer that is much lower than 115 must be wrong. However the life expectancy can be a slowly varying function of age, and in the extreme case may approach a finite value. In which case, the correct answer can be much larger than the age of the oldest person alive. For example, the life expectancy in principle could level off at 2 years, in which case we would not know if there is a correct answer for this problem. Or if the question was posed differently, instead of year, if David had asked at what age you would have a life expectancy of 1 month, again there would not be a correct answer to the question.

There is a branch of engineering called reliability engineering where people analyze such thins as the lifetime of a transistor, which is important to predict how long your computer will last. In most cases the lifetime of products do level off at a finite value.


[/ QUOTE ]

Yep! Very nice points.

[Position]

[ QUOTE ]
Can you post the years for the other ages?

[/ QUOTE ]

The whole chart is at:
http://www.retirelink.com/education/LifeExpectancy.html

I'd found the link elsewhere in this thread.

[PseudoPserious]

Erm, I meant "on morning TV talk shows", not just "on morning". Not that I really watch morning TV talk shows, of course.

PP

[Louie Landale]

No they don't count. Neither are they people.

[Louie Landale]

Does a 110 year old with a life expentancy of 1 year mean that there are exactly half as many 111 year olds as 110 year olds?

[Louie Landale]

Your question presumes there is a well-formed curve for survival that diminishes smoothly. But it can easily be the case that many folks die in their 90s leaving only those with great survivability left over. If so, a 95 year old may have an expentancy of less than a year but a 105 year old may have one of 2 years.

In 3rd world countries it IS that way: new-borns die readily but toddlers do not.

An excessive example is presuming the "importals" of the show "Highlander". Almost everyone older than 130 is an "immortal" and isn't likely to die any time this century.

- Louie

[Navers]

[ QUOTE ]
In 3rd world countries it IS that way: new-borns die readily but toddlers do not.


[/ QUOTE ]

The question was referring to Americans, not those living in third world countries.