Rod Speed wrote:

NY wrote
[...]
OK. So this all hinges on the fact that the birth rate (and maybe death
rate) varies throughout the year.

Yes, and all you need is the birth day to vary, the
death day doesn't need to to get the statistical quirk.

That makes sense. Birth rate is under human control (to some extent)
and shows annual peaks, but while death rate only shows general seasonal
trends. If the birth rate is peaky by calendar date and the death rate
is flat, more of the deaths will be on days which coincide with
birthdays - not because there are more deaths on those days but because
there is a greater chance that each dead person had been born on that
day.

but... if the death rate were also peaky and the peaks didn't coincide
with the peaks of the birthdays, the effect could be reduced or even
reversed. This could happen if voluntary euthanasia becomes more
widespread.


--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk