Trivia

Hard

In Your Average School Class There Is A 50% Chance Two People Share What?

A Birthday
Great-Great-Great Cousins
Ear Wax Type
Blood Type
A graph depicting Birthday Paradox calculations.
Rajkiran g/Wikimedia

Answer: A Birthday

In the field of probability theory, there is a problem known as the Birthday Paradox concerning the probability that in a selection of N randomly chosen people, some of them will share a birthday. This probability reaches 100 percent once you reach a sample size of 367 people (to account for the 366 potential days, including Feb. 29th, +1).

What’s fascinating, however, is how quickly the probability of sharing a birthday climbs. In a group of 23 people, around the size of a small class, the chances of two people sharing a birthday have already climbed to 50 percent. To get to 99 percent, you’d just need to gather two classrooms together. In a group of 57 people, there is a 99 percent chance that there is a common birthday.

While this might seem like something of a mathematical parlor trick, the math behind the Birthday Paradox has actually been successfully employed as a well known cryptographic attack, the Birthday Attack, which uses probabilistic modeling to reduce the complexity of cracking encryption hash functions.

Trivia

Easy

Which Comedy Group Can We Thank For the Naming Origin Of Spam Email?

Trivia

Hard

To Aid In Maintenance Urban Planners In Melbourne Australia Assigned Email Addresses To What City Feature?

Trivia

Hard

Armenians Experienced An Internet Blackout In 2011 Thanks To What?

Trivia

Easy

The Childhood Illness Known As “Rickets” Is Caused By A Deficiency Of?

Trivia

Hard

The Opposite Of A TV Show “Jumping The Shark” Is?

Trivia

Hard

Which Mission Was The First And Only Time “Astronaut Ice Cream” Flew In Space?

Trivia

Hard

Informally Called “Hole-In-One” Insurance, The Formal Name For This Insurance Is?

Trivia

Hard

Which Letter Appears Once a Year on the Moon’s Surface?

X H
J Y

Trivia

Hard

The Largest Earthworms In The World Are Found In?

Trivia

Hard

The Largest City In The World That Is Inaccessible By Road Is Located In?