this may surprise you…
Not a lot of people can get their mind around this at first glance. So what is this paradox anyway? We have seen some cool ones like the double – slit experiment which can sort of be described as such. There are also some other viral ones making their way around the internet. But what about this one? Just about everyone has been in some sort of a classroom before and everyone has a birthday 😉
Imagine sitting in a classroom. Let’s say there are 30 people in the class. What are the odds that two people in the room have the same exact birthday? Mathematician Amir Aczel poses this question to a packed auditorium and engages the front rows in what is known as the “birthday problem.” The results may surprise you.
Ok so do you have any prelim guesses on this or strategy for solving it?
Does this involve algebra or more advanced statistics?
Let’s solve this math riddle in the video on page 2
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1:695
ehhh maybe 1:665… according to my logic, but I see that is apparently erroneous according to the experts.
Well, the process would be; Figure out the total number of “days lived” in the classroom and divide that by 30…Anything beyond that, is probability and logic.
1/365
Shocking? More like high-school arithmetic.
Yeah but I see what he’s saying. If it was a system each box would have one. But it’s not a system so it’s more likely for a box to hold more than one instead of one. Could this be applied to planets and life? If each planet got one than there would only be deer, or squirrel, or human, not a variety. But since it’s not a system there are many on many planets, and none on a lot of planets.
truth is easy to understand, not complicated.
so im sure anyone can grasp this truth at first glance.
I remember this being kicked around in a statistic class I took in college way back in the late 60’s. It’s much better than 1/365.
Reason, we are not talking about one specific day like June 12th (my birthday). We are talking about any 2 people having the same birthay no matter what day. I remember the odds are actually pretty good.
Fucking video
I haven’t hit the link yet but I assume it’s fairly higher than expected because of congregations of random chance caused by many factors such as periods of time during the year the conception rate increases, etc…
That’s sbsolutely false! Number of days accrued and added up would have no bearing here. It would be number of days in a year versus the number of chances I.e. Students but that is only if everyone in the world evenly being divided among the different days of the year. Further, probability is exactly what he’s talking about and the probability is much higher due to convergence of birthdays due to outside factors. This can be measured and from that you get statistical probability.
Also your use of the word logic reveals you as a pseudo intellect. The whole process is logical maybe you meant rational analysis or reasonable assumption?
That’s not a paradox.
You actually only have one “birthday” every year is just an anniversary of you being born.
I think you’re the pseudo intellect, James.
I’m going to say a little bit higher than 1 in 12. Let’s say my birthday is Jan 1 (can chose any day, just using it as an example). I go the first person – what are the odds that their birthay is Jan 1? With no other info, we have to say 1/365. The same with the second person – so now the odds that either of them share my birthday is 2/365. The third person makes it 3/365, & etc. After 29 other people, the odds that ANY of them share my birthday are 29/365, or not quite 1/12.
I retract this. That is the odds that anyone of the other 29 share a birthday with some specified individual. However, they could share birthdays with each other.
New guess: 30 in 12.5, or about 2-to-1 in FAVOR of any two of them sharing a birthday.
I’ll probably have to retract this one too after further thought, but this is my current best guess.
That had to be one of the worst explanations I have ever heard. It maybe true, but the explanation in the video left a lot to be desired.
Nope, that’s wrong too. Final answer, Regis: about 1.19-to-1 in favor.
Odds of any two having the same birthday: 1 in 365. Odds of a third person having the same birthday as either of the first two: 2 in 365. Then 3 in 365, on up to 29 in 365. (29+28+….2+1)/365 = about 1.19.
In junior high I met a guy who was born in the same hospital the same day
I like this one
Okay so here we go I have 4 friends therap girls and we share the same birthday and then this will really freak you out I was mixing a band the band head three guys named Mark and me running sound I also name is Mark our birthdays were all the same day only a few years apart and basically born on almost the exactly same time
Mr. Parker, nowhere did I mention years lived. We also can’t assume the 30 people are students. We cant assume anything, thus, the truest answer we can get without more info is, 30:total days lived
And we arent looking for same birthday each year, but the same exact date of birth
There is no paradox here. With that said, birthdays are not randomly assigned. It is well understood that because of human biology, some months are higher for births, and some are lower. There is 0 surprise that birthdays are clustered. Maybe I just stumbled upon the “mathematician vs biologist quandry”
All I can say is, I have over 365 friends on my fb page, and none have my birthday so, what does that mean? It’s just a random event with numbers that takes place, nothing special. If you win the lotto then you win the lotto, and that’s it.
The statistical probability they’re referring to has to do with the day of the year, not the full date including the year.
Maybe people born around the same time have similar likes and dislikes, similar personality traits that increase the likelihood of them ending up at the same event at the same time.
I bet you can figure it out with a sine wave and base 60 mathematics.
It would be more surprising if and less probably if noone had the same birthday, as if the birthdays were so evenly distributed among the days that noone matched.
With 23 random people in the same room, the odds are 50.8% that two of the people in the room have the same birthday. Assuming a 365-day year.
This is the most pointless thing I’ve read today
Sal Barone
That’s because they explain traits every single human has.
opposing traits
You got it. Good job. There is a slightly easier way to solve using factorials, I seem to recall.
Earl got it. It’s easy if you use factorials. You would do this example in a Probability & Statistics 101. I think it’s fun to read the comments and watch people trying to work out the solution (or in some cases the question!). Thanks for posting Adam
This click bait was designed for people who don’t understand math or what a paradox is.
There’s no paradox here at all.
I think I’d look to see how many sets of twins are in the class
It’s saying that there will be a match 90% of the time when there’s 40 people, not that all 40 people will have a match. There will be at least one match. So out of your 365 friends how many matches are there. I would guess at least 20 but probably more.
Well I was in a class with 2 other people that shared my birthday before…
I think they are clustered because people bang more in the winter, cause it’s cold and there is nothing to do. Hence the summer babies
What are the chances that you, your father in law, and your step mother all have the same birthday? ….for real.
It’s not a paradox. Just plain old statistics, which is actually a pretty cool subject.
Threeve
Mitchell Ryan Stevens Pretty interesting
I can’t even balance a checkbook
Because, Math!
People who have good valentine’s have Nov. Babies, good Xmas have Sept. Babies so for and so on paradox solved