What is the probability of getting heads on one flip of a fair coin?
Answer1/2
A fair coin has two equally likely outcomes, so heads has a 1 in 2 chance.
Science · Facts & stats
Risk facts & stats
7 fact-checked facts about risk and probability, each with the reason behind it. 5 more are in today's round and join this page after it closes.
The basics
In risk assessment, risk is usually described as a combination of likelihood and what?
AnswerImpact (severity)
Risk weighs how likely something is against how serious it would be.
Going deeper
What is 'expected value' in probability?
AnswerThe average outcome over many repeats
Expected value weights each outcome by its probability, giving the long-run average.
When rolling two fair dice, which total is the most likely?
Answer7
Six of the 36 combinations add up to 7, more than any other total.
What is the probability of an event that is certain to happen?
Answer1
Probabilities run from 0 (impossible) to 1 (certain).
Expert level
How many people must be in a room for a better-than-even chance that two share a birthday?
Answer23
With 23 people the chance of a shared birthday passes 50%, the famous birthday paradox.
What is the probability of drawing an ace from a shuffled standard 52-card deck?
Answer1/13
There are 4 aces in 52 cards, and 4/52 = 1/13.
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