Free Maths Calculator

Expected Frequency Calculator

If something has a known probability, how often should it happen over many attempts? Multiply the probability by the number of tries. The answer is what you would predict on average rather than a guarantee, which is exactly the distinction exam questions test with the word expected.

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    Worked Example

    A fair dice is rolled 120 times. How many sixes would you expect?

    1. The probability of a six is 1/6
    2. Expected frequency = probability × number of tries
    3. Multiply:1/6 × 120 = 20

    Answer: 20 sixes

    Try These Yourself

    A coin is flipped 50 times. How many heads are expected?Show answerHide answer

    Answer: 25

    1/2 × 50.

    P(red) = 0.3 and there are 200 spins. Expected reds?Show answerHide answer

    Answer: 60

    0.3 × 200.

    Does expecting 20 sixes mean you will get exactly 20?Show answerHide answer

    Answer: No

    It is an average prediction, not a guarantee.