From this article today: http://news.yahoo.com/s/ap/20071005/ap_on_re_us/odd_shared_birthday
A couple in Ohio gave birth to their third child, each born on Oct. 2. The odds of a family having three children born on the same date in different years are about 7.5 in 1 million, said Bill Notz, a statistics professor at Ohio State University.
I don't understand why the answer wouldn't be (1/365) to the third power, or 1 in 48,627,125?
2007-10-05 08:52:53 · 4 answers · asked by Wheels 4 in Science & Mathematics ➔ Mathematics
becuase it is only taken to the 2nd power.
the first year there are really no odds at all as it is not repetative it is just 1 in 365, to have achild on the same date on a different year is 1/365 to the 2nd power ( 1 in 133,225). This is the same odds as having a third cahild born on the same day because the 3rd birth only needs to match the birth of one child (since both are the same date) so the chances of him being born on the same day is the same odds as the second child being born on the same date as the first child. (1 in 133,225 or 7.5 in 1 mil)
2007-10-05 09:13:42 · answer #1 · answered by chrchll129 3 · 1⤊ 0⤋
Late in answering, but in total agreement with the answers above mine. The probability of the first kid being born on a certain date is (365/365), because any day is valid as a starting point. The restrictions exist only for the second and third, who *have* to be born on the same certain day as the first.
(365/365)(1/365)(1/365) = 1/365² = 1/133225.
Out of every million possible trials,
1000000/133225 = 7.5061-ish will be born on the same day.
2007-10-05 09:23:49 · answer #2 · answered by Louise 5 · 1⤊ 0⤋
Yours would be true if I was calculating that all three children were born on a specific day. But, because there are 365 days in a year, you have 365 choices, so u need to multiply by 365. giving you 1/365^2
2007-10-05 09:20:24 · answer #3 · answered by quickster94 3 · 1⤊ 0⤋
you could get twins, and triples, born on the same day * in the same year *
if this is not the case then only the day is relevant ( since it is not possible to get more than 2 babies in the same year that are not twins or triples.
hmm mistake from me.
all three are born in different years...
so then it is (1/365) ^ 2. the first baby born on any day, the 2nd and third on the same day as the 1st one.
2007-10-05 08:57:19 · answer #4 · answered by gjmb1960 7 · 1⤊ 0⤋