
An Analysis of the Distribution of Birthdays in a Calendar Year (2001) - sabon
http://www.panix.com/~murphy/bday.html
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arjunrc
I love this inference from the data.

 _An examination of the histogram shows significant seasonal variations. The
months July - October show higher than expected births and March - May show
the most significant decline in births. Perhaps the most reasonable
explanation is that conceptions are up in the months of October through
January and down in June through August. You be the judge._

Wonder if HN has an explanation as to why :)

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jedberg
This data is from North America, and it gets cold and people stay in more
October to January.

It would be interesting to see if the trend is reversed in the Southern
Hemisphere, although you'd be hard pressed to find anywhere that gets as cold
in the winter as North America does that has a similar wealth as North
America.

~~~
molmalo
For similar latitudes, maybe New Zeland, and some places in the Argentine
Patagonia.

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theophrastus
I wonder what sort of bias might be introduced by starting out with those who
bought life insurance? At the least this likely under represents folks at both
ends of the wealth spectrum.

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folli
So you're proposing a correlation between wealth and the date of birth?

~~~
theophrastus
more along the lines of wondering if to be included in the analysis requires
buying life insurance if that results in a properly random sample of the
entire population

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zenpaul
There is a noticeable Christmas effect, with birthdays down then and up 9
months later.

I wonder if this has changed in more recent years with changes in
demographics.

~~~
kijin
Interestingly, Boxing Day (Dec 26) has noticeably fewer births than any day
except Feb 29. I wonder if that's related to Christmas as well.

~~~
molmalo
I bet that scheduled c-sections play a role in that...

