Predicting the Future
Predicting the Future
If you flip a coin 100 times, how many heads would you expect? If a factory produces 1000 items and the probability of a defect is 0.02, how many defective items should they expect? Expected frequency helps us make predictions about what should happen in the long run.
This concept bridges the gap between theoretical probability and real-world planning.
Mathematics glossary
- What is expected frequency?
- The number of times we would expect an event to occur in a given number of trials, based on its theoretical probability.
- What is relative frequency?
- Relative frequency = frequency of event / total number of trials. It is also called experimental probability.
Earn the mark scheme marks
Exam Tips
- Use the formula - Expected frequency = Probability × Number of trials
- Be clear about probability - use experimental or theoretical as appropriate
- Round sensibly - you can't have 15.7 people, so round to 16
- Show your working - write the probability and number of trials clearly
- Check reasonableness - does your answer make sense?
Now try it yourself
Quiz · Question 1 of 14
Which formula correctly gives the expected frequency of an event?
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This topic in real past papers
Every real exam question we've found on expected frequency, with a full worked answer.
AQA Paper 1
Two of the four sittings we have full papers for test a probability calculation beyond a single event, one using expected frequency and one using systematic counting.
AQA Paper 2
Two of the four sittings we have full papers for use relative frequency from real recorded data to estimate a probability, then reason about how reliable or how it should be used.
AQA Paper 3
Two of the four sittings we have full papers for give a relative frequency and ask for an actual frequency, or a comparison between several actual frequencies, to be worked out from it.