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Misunderstanding Randomness

Age 11 to 14
Challenge Level Yellow starYellow star
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Some definitions

random:
A term used in probability, relating to things that happen by chance. It means that there is no special pattern to the items or numbers that are selected or chosen, that is, they happen in a haphazard way.

random experiment:
Some process that is carried out according to a set of rules. The rules determine completely the process that we carry out, but they do not tell us in advance what the outcome of the experiment will be. A random experiment can be repeated arbitrarily often.

random number:
A sequence of randomly generated numbers, where all the numbers had an equal chance of being picked, every time. Tables of random numbers used to be printed in books, these days they're usually simulated on computers/calculators. They are used to select random samples in statistics.

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Master Minding

Your partner chooses two beads and places them side by side behind a screen. What is the minimum number of guesses you would need to be sure of guessing the two beads and their positions?

Racing Odds

In a race the odds are: 2 to 1 against the rhinoceros winning and 3 to 2 against the hippopotamus winning. What are the odds against the elephant winning if the race is fair?

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The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.

NRICH is part of the family of activities in the Millennium Mathematics Project.

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