Probability
How likely something is, from 0 (impossible) to 1 (certain), often written as a percentage.
In plain English
A probability of 0.5 is the same as 50%, or 'as likely as not'. Probabilities of separate events combine in ways our brains handle badly, which is why many results feel surprising when they are not.
Uncle Gary explains
The probability that Uncle Gary mentions 2008 at a family dinner is not technically 1. It is close enough that the cousins have a drinking game about it.
Why it matters for your money
Most bad money decisions come from misjudging probabilities: overrating rare big wins and underrating common small losses.
Where we tested it
- The Birthday Paradox Explained at a Wedding
- How Many Bad Days in a Row Before the Universe Is Against You?
- Where Do Missing Socks Go? A Statistical Investigation
- Why You Always Pick the Slowest Queue
- Lesson 4: Probability Without Tears
- What Does a 30% Chance of Rain Mean? The Weather App Didn't Lie
- Lesson 20: The Binomial Distribution: How Likely Is 6 Out of 10?
Related terms
All glossary terms. Educational content, not financial advice.