## / How likely is this . . . ?

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Over the past 18 months or so I've gotten to know two women , the first ( Angela ) is 40 years old & born on the 15th of May .

The second Sarah is 39 years old & also has a birthday on the 15th of May . No biggie , but here is the thing . .

Both Angela and Sarah lost their dads when they were 6 years old , their dads were both 36 years old when they passed .

How likely is it that I would meet & get to know these two people who have never met each other & live hundreds of miles apart ? And should I be perturbed ?

Have any other UKCers discovered similar things ? I am a little curious .
In reply to Boogs: Both myself and my brother married women who's birthday is 31st October.
Not as freaky as the deaths thing but I have wondered the same thing.
> (In reply to Boogs) Both myself and my brother married women who's birthday is 31st October.
> Not as freaky as the deaths thing but I have wondered the same thing.

birthdays have a specific problem named after them for just how counter intuitive the chances of having the same birthday is.

http://en.wikipedia.org/wiki/Birthday_problem

In my primary school, there was a family with three children in three different years who all shared a birthday with their Dad. That's probably more likely than I intuitively think it is, but it's not something I have come across since.

My twin daughters have partners with the same surname and the same initials

The odds of any 'coincidence' like this might be astronomical in advance, but in retrospect there are so many things that could have been coincidences that it's extremely likely that one of them will be. Apparently remarkable things are often remarkably unremarkable.

Thats an interesting link and formula , some good relevant links at bottom of page , should keep me busy for a minute or two !
In reply to Boogs: It is probably more likely than you might imagine. I think there was a thing on More or Less about the chances of meeting someone who shares your birthday and that is quite high too.
> Should I be perturbed ?

Yes, if you can think of another explanation beyond this being a coincidence that is perturbing. If not, then probably not because it's just a coincidence!

If I repeatedly toss a coin and a hundred heads fall consecutively, would you be perturbed, or think I was born with a 'lucky' gene? Or would you laugh surprisedly at the coincidence?

Though on saying this, I'm reminded once of a friend who when anything improbable happened, would declare to me that "I don't believe in coincidences". Then she would smile enigmatically. She was 'spiritual', you see. I'm sure she would declare now that my suddenly thinking of her in relation to leaving an answer to this thread in the midst of an otherwise featureles working afternoon was 'meant to be' and had a reason!

I'm sure you are right EBG but can't help thinking its a little strange .

Another one that had me going hmmmm for a moment or two was the fact that I had a younger brother called Tristan ( My name is Leon ) and there were two brothers in the same small hick town who were roughly the same age also called Leon and Tristan .

Only really thought that a little curious as they are not very common names .
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> I'm sure you are right EBG but can't help thinking its a little strange .

So either 1) The world is magic or 2) Your grasp of probability isn't that great?

Certainly a lot of people manage to misinterpret 2) as 1).
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> Only really thought that a little curious as they are not very common names

But the kind of parents who would call one son Tristan are unlikely to call the other one Dave....

I bet you used to love "Arthur C Clarke's World of Strange Powers" on ITV on a Saturday night

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> Though on saying this, I'm reminded once of a friend who when anything improbable happened, would declare to me that "I don't believe in coincidences". Then she would smile enigmatically. She was 'spiritual', you see. I'm sure she would declare now that my suddenly thinking of her in relation to leaving an answer to this thread in the midst of an otherwise featureles working afternoon was 'meant to be' and had a reason!

Cor it's just like that Nicolas Cage movie "Knowing"
In reply to victim of mathematics:
> [...]
>
> So either 1) The world is magic or 2) Your grasp of probability isn't that great?
>
> Certainly a lot of people manage to misinterpret 2) as 1).

Yep all of the above & my maths is a bit crap as well ;o) .

In reply to Boogs: Sometimes you just have to dig deeper. When I was young the ONLY Randalls in the Sheffield telephone directory were me and my direct family. When we looked in other areas we did not find any Randalls. Imagine my surprise therefore when I was staying in a Hotel in Bournemouth on business and a call came over the speaker system "Alan Randall please come to reception" and 3 of us turned up. Since then I have discovered that it is a far more common name than I at first thought. In fact Tom Randall keeps getting mentioned on this forum but as far as I am aware we are not related.
> [...]
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> But the kind of parents who would call one son Tristan are unlikely to call the other one Dave....
>
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> I bet you used to love "Arthur C Clarke's World of Strange Powers" on ITV on a Saturday night

Arthur used to creep me out a bit to be honest , I was more into Daisy from Dukes of Hazard & Wonder Woman to be honest , thats when I wasn't running around pretending I was the Incredible Hulk . 80)

> How likely is it that I would meet & get to know these two people who have never met each other & live hundreds of miles apart ? And should I be perturbed ?

It is extremely unlikely.

Similarly, when I was driving in to work this morning, I saw a car with the registration number "SG04 XPB". I have subsequently calculated that the probability of this happening by chance is about 1 in 30 million!

> Similarly, when I was driving in to work this morning, I saw a car with the registration number "SG04 XPB". I have subsequently calculated that the probability of this happening by chance is about 1 in 30 million!

not really. I am stalking you and am a bit crap at the hiding bit so surprised you dont see that more often.

ps. shouldnt it be the custom plate ARW 357?

> not really. I am stalking you and am a bit crap at the hiding bit so surprised you dont see that more often.
>
> ps. shouldnt it be the custom plate ARW 357?

Nice. I remembered the gist of it, but not the details.
In reply to Boogs: Chance not only allows coincidences - it compels them.
I was born 10 minutes after someone I now work with.

we both have an SPA

she is a girl and I am not, but we both have blue eyes

spooky
In reply to Boogs: You think you've got problems.

Every girlfriend I've ever had had a birthday on the 4th or 14th of June or July.

My wife's birthday is the 14th July.

Her mother's birthday is the 4th June (for the avoidance of doubt, my mother in law has not been either my wife or girlfriend)

Tomorrow is Independence Day, the 4th July, which I know is a significant date and therefore always makes me nervous. The 14th July also happens to be Bastille Day, another significant date, so that doesn't help.

This is the season of unease. It lasts for just over a month, even though I now have my wife's birthday pegged to Bastille Day. However, that always takes a little bit of processing before I arrive at the right answer.

Mock if you wish, but I've been living with this nonsense for over 30 years

> If I repeatedly toss a coin and a hundred heads fall consecutively, would you be perturbed, or think I was born with a 'lucky' gene? Or would you laugh surprisedly at the coincidence?

I would be suspicious, the most probable explanation is that your coin has a head on each side!
So you've met two people who share 3 facts about their lives. How many other facts are different? Do they have the same hair colour, surname, qualifications, shoe size, aunt's first pet's name, or favourite toothpaste?
Out of countless thousands of pieces of information about them, 3 happen to be the same. But these are the three that you notice, the rest are different so you ignore them.
The human mind sees patterns where none exist.
In reply to victim of mathematics:
>
> The odds of any 'coincidence' like this might be astronomical in advance, but in retrospect there are so many things that could have been coincidences that it's extremely likely that one of them will be. Apparently remarkable things are often remarkably unremarkable.

This

If you took two random women and asked the odds of any particular coincidence, it's pretty unlikely.

For example, the chances of them sharing a birthday are 1/365.

However if you look to your entire group of aquaintences, the chances of any two people sharing a birthday rise rapidly. As that wikipedia page mentioned, it's 50% when the group numbers 23. I'm sure you know more people than that so it's almost certain you know a pair of people with matching birthdays.

Then factor in the fact that you didn't initially start off by wondering about your particular coincidence, but noticed it along the way. They could share initials instead or anything else.

The chances of you knowing two people who share some ridiculously unlikely coincidence is ridiculously likely, so long as you don't pick the people and the parameters a priori.

It's not widely known that probability and statistics are very interesting subjects.