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Rod Speed Rod Speed is offline
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Default OT: Latering thinking puzzle "Why do more peoplre die on their bithday than any other day?"

NY wrote
Rod Speed wrote


It will be interesting to see how many others never get it.


As far as I remember of the postings so far to this thread, you and Mike
Humphries are the only ones who have asserted that it is true.


Yes, but hardly anyone else commented at all and no one denied the original.

Mike has given a fairly rigorous explanation of probability for each
successive day after today; you have said "the variation in the birth rate
over the year is all that is needed to explain it", without explaining
*why* a varying birth rate means that there is a spike in the probability
of dying exactly n calendar years after the date when a person was born.


Thatís where you keep failing to understand. It doesnít matter when they
die day wise, the ONLY thing that matters is that some days of the year
have more BIRTHS than others. THATíS what produces the statistical quirk.

I can see that more people will be born on some days than others. So if
you took a sample of people, you'd expect to find more people with some
birthdays than others.


And thatís why the death is irrelevant. It just more likely
that the death will occur on the same spike days.

But even assuming a constant death rate (ie not varying seasonally), I
don't see how that explains why person A, born at a time of high birth
rate, is more likely to die on their birthday, whereas person B, born at a
time of low birth rate, is more likely to die on their birthday.


That isnt what happens. Its just more likely that they will die on a spike
day.

What is so special about a period of exactly one calendar year that makes
a person more likely to die then than any other day.


Nothing, its just simple stats that spike days have more with the birth day.

What is interesting is that this statistical analysis of probability of
dying on any day, and the sudden increase on the person's birthday, isn't
mentioned in the Wikipedia article, which constrains itself to variations
due to factors that are (loosely!) within the control of the person:
accidents while celebrating, suicide as people think "I'm a year older -
is life still worth living", terminally ill people striving to stay alive
until their next birthday (or the wedding of a family member or any other
significant date).


That stuff is also relevant but isnt the reason
the obnoxious person was referring to.

I think I'm just going to have to accept that there *is* a reason for it
which I don't *really* understand


It will be interesting to see if you ever do.

- either because you have given an "obviously" jump of logic


There is no jump of logic involved, ALL that matters is
that birth days have spikes for various obvious reasons.

from "more people are born on some days than others" to "therefore a
person is most likely to die on their birthday", or because Mike's
explanation involves summing lots of infinitesimally small probabilities
("if I'm alive today, what's the chance I'll be alive tomorrow; if I'm
alive tomorrow, what's the chance I'll be alive the next day" ad
infinitum).