German Baby-Making: Spurts and Stalls
What was going on in Germany in April of 2001 that so distracted people that many of them forgot to get busy making babies that month? And when the sudden forgetfulness was likely noted shortly after January of 2002, did the Germans feel guilty and make a concerted effort to get back on track by getting extra busy in March of 2002, or was there a massive power failure which left people with little to do but seek their own form of entertainment?
Check this graph of Germany’s birth data and note the deviation from expected norms in the months of January 2002 and December 2002. I’ve graphed 10 years of data and the monthly average for births in January is 62,881, usually in a narrow range of 59,000-65,000 but in January of 2002 the births dropped to 47,613. Then to close out the year there were 73,104 births in December when the monthly average is 61,916 ranging between 56,000 – 67,000.
What I’ve done for the graph is taken the annual mean and then charted the monthly variance from the mean. Quite clearly there are annual cycles to conception (and these vary by country – more data in subsequent posts) and there are two very noticable deviations from the norm in 2002.
So, what was going on in Germany back then?
What are the units of the horizontal axis? Percent?
I’ve heard that the power failure = more births nine months later theory is just an urban legend.
What are the units of the horizontal axis? Percent?
Yes.
Employment figures would be my guess.
Data entry error. It looks suspiciously like the data for one political subdivision got credited to the wrong day.
Microsoft Excel, the chainsaw of statistics … (Or is it the rototiller of statistics?)
Ignoring the anomolous data for Dec and Jan in one year, the story seems to be why are births bunched up in July?
Oktoberfest.
The absolute value of the December and January 2002 variances off the mean is just about exactly the same. And both those values are about twice the next-highest values. Kinda stinky.