The Blog
Everyday Numbers
Probability and statistics surprises, explained by counting real things.
Everyday Numbers
The Base Rate Trap
A scanner catches 99 percent of bad parts, and it just flagged yours. The chance your part is actually bad may only be about 9 percent.
Everyday Numbers
The Birthday Surprise: Why 23 Is Enough
In a room of just 23 people, two probably share a birthday. It sounds wrong until you count pairs instead of people.
Everyday Numbers
The Bat and the Ball
A bat and a ball cost $1.10 together, and the bat costs a dollar more. Your first answer is probably wrong, and that is the interesting part.