Randomness

Africa has 54 of the world’s 195 countries, so a random country wheel lands there 27.7% of the time. Here are the odds for every continent.

In a group of just 23 people there is a 50.7% chance two share a birthday. With 30, it is 70.6%. Here is the full table and a classroom experiment to try.

With 100 tickets and 3 prizes, holding 5 tickets gives you a 14.4% chance of winning something, not 15%. Here is a simple table of raffle odds.

Drawing names from a hat for Secret Santa? In a group of 5 or more, about 63% of draws have at least one person pulling their own name. Here is the maths and a fix.

A study of 350,757 real coin flips found coins land on the side they started on 50.8% of the time. Here is how coins, dice and online wheels compare for fairness.

In a classic study, 28% of people asked for a random digit from 0 to 9 chose 7, almost three times what chance would give. Here is why humans make poor random number generators.

Spin a 10-name wheel 10 times and there is a 62% chance the same name wins twice in a row at least once. Streaks and repeats are what real randomness looks like.

With 10 names on a wheel, it takes about 29 spins on average before everyone has been picked at least once, and 1 time in 10 it takes 44 or more. Here is the full table.

We ran one million spins of a 10-name wheel using the same secure random generator our wheel uses. Every name won between 99,470 and 100,597 times, within 0.6% of a perfect split.