Here it comes again. Many years ago I have learned, that if it’s the 13th day of the month, then it is a little bit more likely that it’s Friday, than any other day.
The Gregorian calendar is a bit biased here, there is nothing you can do about it.
Later I wondered if some datamining algorithm will uncover this oddity. It should have.
It did. But it also showed that there are some even more worrisome biases here. That for example, the 31st day is even more biased toward Wednesdays.
This dataminig story happened in some more innocent times, of course. Perhaps I’ll write more about this at some Wednesday the 31st.