> >e iSadly, I didn't mean anything so clever. Among finance/econ geeks, E is
>
> also the "expectation" operator. So E(0) in this context is "Expectation
> at time 0". Brad said that life expectancy at birth was the least worst
> measure. I objected that E(0) wasn't equal to E(0)(E(10)) "expectation at
> time 0 of expectation at time 10". Usually, this would be equal to E(0) -
> after all, there's something funny about expecting your expectation to
> change, which is where the reference to "law of iterated expectations" came
> in. But when you're talking about life expectancies, you can expect that
> if you survive until ten, then your expectation of your lifespan will
> change markedly. I suggested that you should be comparing expectancies on
> the basis of life expectancy at the most common age for people to die,
> which, frankly, sounds a lot less silly when you use five-shilling words
> like "modal"
I am still confused.
1) What's the difference between E(10) and E(0)(E(10))? Don't they both represent "how long people who make it to age 10 are expected to live"?
2) If 1) is true, then E(0) can never be equal to E(0)(E(10)), unless noone dies before age 10, right?
3) Wouldn't the modal age of death be tremendously dependent on the interval you choose to distribute deaths? If you do it by month, then you'll get that the modal "month" of death is the one after birth. If you do it by decade, then you'd probably get the 80s (I am just guessing here). If so, then choosing E(modal age of death) doesn't make much sense, does it?
--
Electrical Engineering Home # (607) 272 4808 112 Phillips Hall Fax # (607) 255 4565 Cornell University mailto:enrique at ee.cornell.edu Ithaca, NY 14853 http://peta.ee.cornell.edu/~enrique