I'm pretty sure the word twin can be used for one of the two twinS.
So, as far as I know, nothing is wrong with that sentence.

NX 7.5
Teamcenter 8

So for every birth of twins, there are 58 other births.  That sounds a bit different than the original statement, yet the two are consistent numerically.

Is that the same as 2 out of 60 then, which would make more sense.  You can't have one twin...kind of an oxymoron, eh?

______________________________________________________________________________
This is normally the space where people post something insightful.

Does this mean people are making love twice as much??

Quote (MiketheEngineer):

Does this mean people are making love twice as much??

NO, just twice as effectively

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
http://www.siemens.com/plm
UG/NX Museum:   http://www.plmworld.org/p/cm/ld/fid=209

To an Engineer, the glass is twice as big as it needs to be.
 

I am a (one) twin.

Something about that number 30!  In a room full of 30 people, two will share the same birthday.

f-d

¡papá gordo ain't no madre flaca!

Two birds with one stone. Or is that two stones with one bird??

- Steve
 

You sure about that math Fatdad?

Steve,

...just can't kill the third bird...without some ramifications.

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This is normally the space where people post something insightful.

29 single births, the 30th and 31st are twins, then another 29 single births.

1 in 30 is a twin.

Stats for triplets, well that's a whole different ball game.

KENAT:  Google, "Birthday Paradox."  There'll be plenty of reading.  I've just taken the answer as 30, which is pretty close to the real answer.

f-d

¡papá gordo ain't no madre flaca!

In college, the professor who taught Statistics had a bunch these counterintuitive challenges he would throw out every once in awhile.  He would make some statement like: "If you walked into a room of 30 people, what's the likelihood that someone in the room would have the same birthday as you?" and if students expressed any doubt he'd pull out a $20 bill and offer to make a bet that he was right (he claimed that a person with a good understanding of statistical methods could make a lot money with bets like this at your local bar or pub).

Another favorite of his was betting that you could deal out 25 cards face-up from a well-shuffled deck and by simply moving the cards around the table, come-up with five 'pat-hands'.  He admitted that while the odds may not have been quite as good as was the 'birthday paradox', that one could still do well in the long run as people were more incredulous and would take the bet quicker and the odds were still in his favor enough that he'd offer that wager to anyone at anytime.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
http://www.siemens.com/plm
UG/NX Museum:   http://www.plmworld.org/p/cm/ld/fid=209

To an Engineer, the glass is twice as big as it needs to be.
 

just for the record, JohnRBaker didn't state the "Birthday Paradox" correctly.  It's not the liklihood of somebody having the same birthday as YOU, it's the liklihood that two people will have the same birthday.  The liklihood of one in 30 people having MY birthday would be 30/365ths, or thereabouts. . .

f-d

¡papá gordo ain't no madre flaca!

30/365 assuming none of them can have the same birthday, but giving your previous statement that in a group 30 (or 29 for that matter) people, 2 will have the same birthday, it's more like a 29/365 chance :p



P.S.: math:
1-364/365^30=0.0790085981~=7.9%
29/365=0.0794520548~=7.95%
30/365=0.0821917808~=8.2%


P.P.S: no leap years were harmed during these calculations.

NX 7.5
Teamcenter 8

1-364/365^30=0.0790085981~=7.9%
I think this is the math for one of the 30 having my birthday, which settles to about 30/365.

For any other two having any random but shared birthday, it is a factorial:   since each suceedding person must have any different birthday then the person before, or any person before, then  

   1   -     (364/365) * 363/365   * 362/365   *  361/365    * 360/365      etc.  

Just google the "birthday paradox" and you'll get all the math you need.  It's close to certain that in a group of 30 people two will have the same birthday.  There'd be different odds (much lower) that in group of 30 people one will have MY birthday.

That was all I was clarifying.

f-d

¡papá gordo ain't no madre flaca!

Yes, I realized after I posted my antidotal story that I incorrectly stated the precise wording of the 'wager'.  It should have gone something more like:  "If you walked into a room of 30 people, what's the likelihood that at least TWO of you will have the same birthday?".

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
http://www.siemens.com/plm
UG/NX Museum:   http://www.plmworld.org/p/cm/ld/fid=209

To an Engineer, the glass is twice as big as it needs to be.
 

Slightly better than if you walked into a room with 29 people

Quote (JohnRBaker):

"If you walked into a room of 30 people, what's the likelihood that at least TWO of you will have the same birthday?".

I don't think that you walking into that room has any influence whatsoever on the possible similarity of their birthdays...
 

NX 7.5
Teamcenter 8