The Birthday Paradox: When Do Shared Birthdays Occur?
Discover how many people are needed for a 50% chance of shared birthdays—roughly 23, not 180! 🎂

Vsauce2
14.1M views • Dec 18, 2018

About this video
How many people need to be in a room before there’s a 50% chance that two of them share the same birthday? Is it about 180, since that’s around half of 365? Is it only 100? The real answer is surprisingly much, much smaller.
If you have just 23 people in a room, the odds of whether two get presents on the same day is a coin flip. Get 50 people together and that shared-birthday probability skyrockets to 97%. A handful more and it’s a virtual statistical certainty.
Really? Yes, really! With the aid of tiny plastic babies and some mathematics, Kevin proves and visualizes this surprising veridical paradox.
**** LINKS ****
Birthday Attack Example In Hacking
https://www.youtube.com/watch?v=4shxYyV4O_k
Birthday Attack Hash Collision
https://www.youtube.com/watch?v=18ihbf1EqRw
Hashing Algorithms And Security - Computerphile
https://www.youtube.com/watch?v=b4b8ktEV4Bg
Discussion On The Birthday Attack
https://www.youtube.com/watch?v=2bEL3ok8D70
The Birthday Attack
https://danielmiessler.com/study/birthday_attack/
***********
Vsauce2 Links
Twitter: https://twitter.com/VsauceTwo
Facebook: https://www.facebook.com/VsauceTwo
Hosted, Produced, And Edited by Kevin Lieber
Instagram: http://instagram.com/kevlieber
Twitter: https://twitter.com/kevinlieber
Website: http://kevinlieber.com
Research And Writing by Matthew Tabor
https://twitter.com/matthewktabor
Huge Thanks To Paula Lieber
https://www.etsy.com/shop/Craftality
Get Vsauce's favorite science and math toys delivered to your door!
https://www.curiositybox.com/
Select Music By Jake Chudnow: http://www.youtube.com/user/JakeChudnow
MY PODCAST -- THE CREATE UNKNOWN
https://www.youtube.com/thecreateunknown
If you have just 23 people in a room, the odds of whether two get presents on the same day is a coin flip. Get 50 people together and that shared-birthday probability skyrockets to 97%. A handful more and it’s a virtual statistical certainty.
Really? Yes, really! With the aid of tiny plastic babies and some mathematics, Kevin proves and visualizes this surprising veridical paradox.
**** LINKS ****
Birthday Attack Example In Hacking
https://www.youtube.com/watch?v=4shxYyV4O_k
Birthday Attack Hash Collision
https://www.youtube.com/watch?v=18ihbf1EqRw
Hashing Algorithms And Security - Computerphile
https://www.youtube.com/watch?v=b4b8ktEV4Bg
Discussion On The Birthday Attack
https://www.youtube.com/watch?v=2bEL3ok8D70
The Birthday Attack
https://danielmiessler.com/study/birthday_attack/
***********
Vsauce2 Links
Twitter: https://twitter.com/VsauceTwo
Facebook: https://www.facebook.com/VsauceTwo
Hosted, Produced, And Edited by Kevin Lieber
Instagram: http://instagram.com/kevlieber
Twitter: https://twitter.com/kevinlieber
Website: http://kevinlieber.com
Research And Writing by Matthew Tabor
https://twitter.com/matthewktabor
Huge Thanks To Paula Lieber
https://www.etsy.com/shop/Craftality
Get Vsauce's favorite science and math toys delivered to your door!
https://www.curiositybox.com/
Select Music By Jake Chudnow: http://www.youtube.com/user/JakeChudnow
MY PODCAST -- THE CREATE UNKNOWN
https://www.youtube.com/thecreateunknown
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Video Information
Views
14.1M
Likes
454.2K
Duration
8:03
Published
Dec 18, 2018
User Reviews
4.9
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