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How to express probability

There are two main methods of expressing probability:

  1. Probabilities are most commonly shown as fractions:

    • The probability of getting 'tails' when you toss a coin is a 1 in 2 chance, or 1/2

    • The probability of getting a 3 when you roll a dice is a 1 in 6 chance, or 1/6

  2. Probabilities can also be shown as decimals or percentages:

    • A probability of 1/2 can also be shown as 0.5 or 50%

    • A probability of 3/4 can also be shown as 0.75 or 75%

The results of an experiment can give different probabilities to those you expect. If you throw a dice six times, you would expect to get a 6 once as the probability of throwing a 6 is 1 in 6. But in fact you might get more than one 6 or no 6s at all!

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