Coincidence | Probability problems | Applied probability | Mathematical problems | Probability theory paradoxes
In probability theory, the birthday problem asks for the probability that, in a set of n randomly chosen people, at least two will share a birthday. The birthday paradox is that, counterintuitively, the probability of a shared birthday exceeds 50% in a group of only 23 people. The birthday paradox is a veridical paradox: it appears wrong, but is in fact true. While it may seem surprising that only 23 individuals are required to reach a 50% probability of a shared birthday, this result is made more intuitive by considering that the comparisons of birthdays will be made between every possible pair of individuals. With 23 individuals, there are (23 × 22) / 2 = 253 pairs to consider, much more than half the number of days in a year. Real-world applications for the birthday problem include a cryptographic attack called the birthday attack, which uses this probabilistic model to reduce the complexity of finding a collision for a hash function, as well as calculating the approximate risk of a hash collision existing within the hashes of a given size of population. The problem is generally attributed to Harold Davenport in about 1927, though he did not publish it at the time. Davenport did not claim to be its discoverer "because he could not believe that it had not been stated earlier". The first publication of a version of the birthday problem was by Richard von Mises in 1939. (Wikipedia).
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."
From playlist Mathematics
The so-called Birthday Paradox isn't a true paradox -- it's a fascinating example of how bad humans are at off-the-cuff probability. Tune in to learn what the Birthday Paradox is and how it works. Whether the topic is popcorn or particle physics, you can count on the HowStuffWorks team to
From playlist Wackiest Comment Threads
The explains that it only takes a group of 23 people to have a 50% chance that two people have the same birthday. http://mathispower4u.com
From playlist Mathematics General Interest
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From playlist Shorts
Birthday Paradox Happy birthday to me! In honor of my birthday, today I'll talk about a really cool paradox in probability called the birthday paradox. It answers the following question: In a group of n people, what is the likelihood that at least two of them share the same birthday? The
From playlist Random fun
Follow-up: Birthday Magic Square
This is my follow-up video to my birthday magic squares video https://youtu.be/hNn0j4Kay8g --- Yeah, I know the audio is messed up. It's not the mic, it's because I recorded via OBS, and that messed up the audio. Sometimes it's difficult to get all the tech working. I tried. If the audio
From playlist My Maths Videos
Birthday Problem Explained Intuitively!
In this video I prove the math behind the classic "birthday problem" or "birthday paradox" in a quick, concise, and intuitive manner. The problem goes... "What is the probability that two people have the same birthday in a room with 23 people?" Note: This is a nice approximation method. I
From playlist Probability and Statistics
It's not the famous Cheryl's birthday problem...According to Mothership, this math problem is causing a lot of confusion: "There are 37 students in a class. How many students, at the least, are born in the same month?" Now I think the problem intended for a slightly more difficult question
From playlist Viral Math Memes
Cheryl's Birthday Problem - It depends on your point of view
Cheryl's Birthday problem was a question in a recent Singapore Maths Olympiad. Here is the problem: You have Albert, Bernard and Cheryl. Cheryl says "my birthday is one of these ten dates" May 15 May 16 May 19 June 17 June 18 July 14 July 16 August 14 August 15 August 17 She gives Albe
From playlist My Maths Videos
4.7.5 Birthday Matching: Video
MIT 6.042J Mathematics for Computer Science, Spring 2015 View the complete course: http://ocw.mit.edu/6-042JS15 Instructor: Albert R. Meyer License: Creative Commons BY-NC-SA More information at http://ocw.mit.edu/terms More courses at http://ocw.mit.edu
From playlist MIT 6.042J Mathematics for Computer Science, Spring 2015
PBS Member Stations rely on viewers like you. Support your local station at: http://to.pbs.org/DonateOKAY ↓ More info and sources below ↓ In case you have a strange new desire to get an IOTBS shirt: http://store.dftba.com/collections/its-okay-to-be-smart#_=_ See if you share a famous bir
From playlist Be Smart - LATEST EPISODES!
Check your intuition: The birthday problem - David Knuffke
View full lesson: http://ed.ted.com/lessons/check-your-intuition-the-birthday-problem-david-knuffke Imagine a group of people. How big do you think the group would have to be before there’s more than a 50% chance that two people in the group have the same birthday? The answer is … probabl
From playlist New TED-Ed Originals
Birthday probability problem | Probability and Statistics | Khan Academy
Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now: https://www.khanacademy.org/math/statistics-probability/counting-permutations-and-combinations/combinatorics-probability/v/birthday-probability-problem The probability that at least 2 people in a
From playlist Probability and combinatorics | Precalculus | Khan Academy
When Is Cheryl's Birthday? Answer To Viral Math Puzzle
This problem went viral after it appeared on a Math Olympiad test for talented students in Singapore. It's not a trick question! Here's the problem, which I have very slightly re-worded for clarity. Blog post (detailed text explanation): http://mindyourdecisions.com/blog/2015/04/14/when-i
From playlist Logic Puzzles And Riddles
Happy Birthday!! What an Amazing Coincidence
Weird Coincidences do Happen
From playlist Bi-weekly Physics Problems