Your Birth Month Maybe?

[sleeplessdragn]

RE: Re: RE: An experiment

26 January

The superbowl has landed on my birthday a few times.

[Kilgamayan]

RE: Re: RE: An experiment

September represent.

[Benny1]

I'm august 26th, I'm pretty much always the youngest in my class, or very close to the youngest.

[Layla-Day]

October 2nd.

[Squeek]

We're in last

Go July...

I knew most people weren't born in the summertime. This just rubs it in.

At least my birthday is far enough from any gift-giving holiday that they do not blend together.

~Squeek

[Kenzya]

June 25

[cutesaru18]

RE: Re: RE: An experiment

August 8th

[evilbutterfly]

RE: Re: RE: An experiment

I can't remember the exact stats, but it's pretty high that somebody here will share a birthday with us. I remember in some algebra class or something, the teacher told us that it was it was more than likely that there was a shared birthday in the class. Once you get up to like, 30 or 40 people, the percent chance of a shared birthday is up in the 90s. It's ridiculous.

Btw Tass, my sister's bday is the 15th too.

[MetsPenguin31]

RE: Re: RE: An experiment

March 6th

[whorlichan]

RE: Re: RE: An experiment

Mine is the 27th of February...I share it with Elizabeth Taylor, who a bunch of my family members work for, so last year none of them came to my party because it wasn't as ritzy and expensively catered as her party was, and didn't have lots of celebrities at it. I also share it with Shiran from my Hebrew school, but she's not as special as Liz. No one went to her party.

Oh--and I was a honeymoon baby. Conceived in Tel Aviv, born in Haifa. I was also a couple of weeks late, and the doctors were threatening to induce my mom on the 29th (1984 was a leap year, of course) but she threatened to get them all fired (because she worked at the hospital too. High-up admin nurse lady thing). And anyway, I choked myself by wrapping the umbilical around my neck like a pretty scarf so I was born by emergency C-section a couple of days after that.

[soccr743]

RE: Re: RE: An experiment

August 26 (4 days older then LD :P)

-----Soccr743-----

[QreepyBORIS]

RE: Re: RE: An experiment

One of my friends was born on August 26th.

My mom shares Synth's birthday. It is not a coincidence.



I was born on June 22nd.

[Squeek]

RE: Re: RE: An experiment

EB, I don't get your teacher's logic.

The odds are 1/365 (366). You'd need 366 (367) people to absolutely guarantee a match.

I doubt a class of 40 has a match in birthdays 90+% of the time. More like 10%.

~Squeek

[soccr743]

RE: Re: RE: An experiment

Actually Squeek you are wrong on this one...

I forget the actual number of people to guarantee a match, however, I remember reading about it in my calculus book for some exploration in some chapter...

-----Soccr743-----

[psychic25]

RE: Re: RE: An experiment

I can't remember the exact stats, but it's pretty high that somebody here will share a birthday with us. I remember in some algebra class or something, the teacher told us that it was it was more than likely that there was a shared birthday in the class. Once you get up to like, 30 or 40 people, the percent chance of a shared birthday is up in the 90s. It's ridiculous.

January 14th

Me too lol.

And that does actually seem to be true, Squeek. In fifth grade, there was someone ELSE with the same birthday as me in my class, too. I have a book about this... here's the passage for everyone:

If you go into a school class, more often than not you will find at least two children with the same birthday. To most people this might seem an unlikely coincidence. After all, there are 365 days in the year, so you might expect that you needed a classroom with about 180 children in it before there was a fifty-fifty chance that there would be a coincidence of birthdays.

However, this is not the case. Surprisingly, you only require 23 children in a class for there to be more than a 50-50 chance that two of them have the same birthday. In fact because birthdays are not spread evenly across the year, if classes had only 20 children you would probably still find that there was a birthday coincidence in half of them.

How can this be? To work it out, you need to konw that in order to calculate the probability of two 'independent' events happening together, you multiply the probability of each of the events together. (And I'm going to skip the explanation for this because I assume most of you know why.)

Like the toss of a coin, one child's birth date is independent of another child's (as long as they aren't twins!). This means that you can calculate the chance of a birthday coincidence by multiplying probabilities together in the same way as for coin tossing. But instead of calculating the chance of a coincidence, let's work out the chance that all of the children have different birthdays- it's actually a much simpler calculation.

Imagine first of all that you have only two children in the class. The first one's birthday is 14 June. What is the chance that the second child's birthday is different? There are 364 other dates to choose from, so the probability is 364/365 that the two children have different birthdays. Sarah now enters the room. Does she have a birthday different from the other two children? If the other two children have different birthdays, then the chance that Sarah's birthday is different again is 363/365 - there are only 363 days left which are different. Simon is next to arrive. The chance that his birthday is different again is 362/365... and so it continues.

As each new child enters the room, the chance of them having yet another different birthday diminishes ever so slightly. The chance of the 23rd child having a different birthday from everyone else is 343/365.

And at this point, let's stop to work out what the overall probability is that each of the 23 children have a different birthday. We calculate it by multiplying the probabilities together, just like in anything else:

The probability of no person having the same birthday as someone else in a room of 23 people=
364/365 x 363/365 x 362/365 x .... x 343/365 = 0.49 or a 49% chance

So the chance of no two children in a class of 23 having the same birthday is 49 per cent, or about half. But what is the alternative to no children having the same birthday, the other 51 per cent? It is that at least two children do have the same birthday. In other words, the chance of at least one birthday coincidence is 51 per cent with just 23 children. This result doesn't feel right to many people, but it is true. Furthermore if you don't believe it then you can test it for yourself with a visit to your local school.