Everyday chance: little traps
Shared birthdays, Monty Hall's doors, dice and coins: your gut will get it wrong a lot
What this quiz asks
- 1You flip a fair coin. What's the probability of getting heads?
- 2With a standard six-sided die, what's the probability of rolling a 6?
- 3You flip two fair coins. What's the probability of getting heads twice?
- 4The Monty Hall problem comes from a TV game where a contestant picks a door. How many doors are there?
- 5Birthday paradox: from how many people is there a better-than-even chance that two share the same birthday?
- 6Monty Hall: you pick 1 door of 3, the host (who knows everything) opens another door hiding a goat. What do you do?
- 7A fair coin lands heads 4 times in a row. What's the probability the 5th flip is heads again?
- 8Birthday paradox, counting only 365 possible days: from how many people is a shared birthday certain?
- 9You roll two six-sided dice and add them up. Which total comes up most often?
- 10A test that's 99% reliable screens for a very rare disease and tells you 'positive'. Why is that often a false alarm?
