The local press reported the following:
"A couple who share the same birthday were stunned when their first son was born on the same day - at odds of 1,014 to one"
As far as I can make out, the odds of the child sharing the same birthday as the parents is 365 to one. The odds of all three sharing the same birthday would be 365 squared (133,225 to one).
So, where does the 1,014 to one figure come from?
Tim
do you really need to ask? :)
NT
The problem has not been stated clearly enough.
1014 *might* be the probability that 3 people share the same birthday.However, it's equally valid to argue that "given these particular parents have a shared birthday on date X, what is the probability that their child will be born on date X" which is 1/365 or 1/366 for a leapyear.
Which is an excellent illustration of how you can talk bollocks with stats :)
A journalist who is a bit dim?
Not the same problem. That's about the odds of people in a group sharing a non-specific birthday. This is either about the child sharing the parent's birthdate or the odds of just them all having the same specific date.
Tim
What's the proability that he isn't the real father. :-)
It's a question of whether:
1) An arbitrary 2 parents + one child share a single birthday;of
2) This specific couple have a child who share's their birthday (their birthdays already being an established event and thus having a probability of 1As I said in my other post, subtle phrasing and some misplaced assumptions make a factor of 3 difference to the result. And we have a self selected generally smart bunch of people interpreting it in different ways, so imagine how easy it is to pull the wool over the general population's eyes!
That's a function of "Dishyness of the Milkman" :)
There is also the assumption that birth dates have a random distribution across the whole year and that there is no clustering around specific dates.
In our case there is a family history of births in early January and in late September.
Which conveniently fall about 9 months after Christmas and Easter.
Which in turn suggests that if there is nothing particularly good on the telly we make our own amusement ;-)
No idea how statistically significant this is.
Cheers
Dave R
My mother and her sister were both born on Nove,ber 8th - two yaers apart.
And no, my grandfather was not a precision grinder.
So how did he manage to get it 365 x 3 -1? = 1094.
Simple, he didn't. Dunno where you're getting your 1094 from when the number quoted was 1,014.
Tim
well exactly. that is the point. No combination of numbers gives 1014..
its 3x338. But where does 338 come from?
1014= 2 x 3 x 13 x 13Which bears no relation to anything.
Not a factorial for sure. It might be several factorials.
AS others have pointed out, the odds of a child being born to two parents *who already share the same birthday*, is ~ 365.25 :1
AS for three random people sharing the same birth date, its a bit higher
- statistics was never a strong suit - But not I think 1014:1
probbaly the EU :-)
They come up with a figure and only 'idiots' don't believe them.
365 x 3 -1 It's quoted above your reply. (Immediately before it.) I shal write this very slowly then go over it to make sure you get it: 365 = the number of complete days in a year. I added three years together to make 1095. Then I found I was stuck with it (1095) But I managed to get it down to 1094 by carefully adding the odds to the sum.
Which was a minus number, that is: I had to add in a "minus number" (called One or "1" in this case, in maths.)
I had derived that number from the chance being one more than the rest (the others being the parents.)
That was the number I was referring to. Do you have the same problem analysing computer systems? I appreciate that 1014 was not a viable number and was trying to find a more viable alternative. We tend to do that sort of thing in this country. My problem in understanding you is that I don't know what country you come from.
I have heard that in a certain part of the Amazon, otherwise perfectly good engineers don't count in linear sequences. Do you come from Peru by any chance?
Please don't think I am belittling you. I actually wish that I could count in logarithms.
2, 20, 200, 2,000, 20,000 ...
I appreciate that you've lost your tinfoil hat but even so, you should be able to understand the original question and not invent a method of reaching a figure plucked from the aether rather that the quoted figure.
Still, if it amuses you feel free to derive means to arrive at other irrelevant numbers.
I don't mean to belittle you as I appreciate that without meds, your thinking is disordered.
Tim
Maybe the program cannot calculate odds over a certain value?
Brian
The article was in yesterday's Sun, and also contains the words "Ladbrokes confirmed the odds of Aidan sharing his birthday with not one but both parents were 1,014 to one". It sounds as if Ladbrokes have multiplied the odds for both parents having the same birthday, with odds for sons having the same birthday as the mother, neither of which are likely to be 1 in 365 in actual practice.
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