Dating someone with the same birthday astrology
Dating someone with the same birthday astrology - great tip for dating success
With enough analyses, the probability of finding a significant pattern gets close to one even when alpha is small.
I know that the chances of meeting someone who was born on the same date than me is fairly high and I know a few people with whom I share my birthday although for the little I've read about the birthday paradox, it doesn't take same year into account. Journal of the American Statistical Association 84: 853-861.
As has been noted, both the shared year and shared birthday probabilities could be further refined based on additional information.
When it comes to two people, there are many potential sources of coincidences. Within the domain of date of births, you could imagine many possible similarities: same month; same day of month; same star sign; same birthday, different year; some similarity in the numbers such as 2nd of May and 5th of February; dates are some round number apart (e.g., 8th of May 18th of May); dates are only only some small number apart (e.g., 8th and 9th of May).
I find the amount of factors to take into account quite vast (up to a point, gender and age, availability, probabilities of separation in our region, etc.) Is it even possible to calculate the probabilities on something like this? The chance that your boyfriend was born the same year as you is actually very high (especially given many situations tend to bring people of very similar age together); it's a very difficult probability to calculate.
If you had that probability, P(Same day and same year) = P(Same year) $\times$ P(Same day|same year).
If it's an event specified before the fact, you can simply break it down: The chance that your boyfriend was born the same year as you is actually very high (especially given many situations tend to bring people of very similar age together); it's a very difficult probability to calculate, though, without data.
So if you had some good estimate of P(Same year), you can calculate the overall probability reasonably well.My boyfriend's mother has the same name as my mother! The odds of "some weird connection with my boyfriend" are impossible to calculate. Post Hoc it is essentially guaranteed that there is something very unlikely. You can calculate odds of some particular phenomenon happening, after you know it is, but it's only there because you invented the phenomenon!Don't forget that them knowing they had the same birthday almost surely reflexively brought them closer together around the time they met.I'd guess that P(same year) is roughly of the order of 0.1 to 0.2, but that's just a guess. I've never understood this in terms of evolution, but it seems to be highly correlated.[Edit: Jeromy gives a figure based on actual data, which turns out to be about 17%.] My guess would be slightly lower. However the percentage of same-year relationships is likely much higher in high school.A consequence of this is that the pool of people you know from the exact same ages is by guesstimation a factor of 5 bigger than the expected value, if $age I'm told disproportionally many babies are born just before new year in The Netherlands, where a 31 December birth is financially advantageous over a 1 January birth, due to the way benefits are calculated.