ProbabilityDeep Dive

Calculating Expected Frequency

Part of Expected FrequencyGCSE Mathematics

This deep dive covers Calculating Expected Frequency within Expected Frequency for GCSE Mathematics. Revise Expected Frequency in Probability for GCSE Mathematics with 14 exam-style questions and 12 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 3 of 4 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.

Topic position

Section 3 of 4

Practice

14 questions

Recall

12 flashcards

Calculating Expected Frequency

Formula

Expected Frequency = Probability × Number of trials

Example 1: Coin Flipping

If you flip a coin 200 times, how many heads do you expect?

Expected heads = P(heads) × Number of flips = 0.5 × 200 = 100

Example 2: Quality Control

A factory knows that 3% of its products are defective. In a batch of 500 items, how many defects are expected?

Expected defects = P(defective) × Number of items = 0.03 × 500 = 15

Using Experimental Probability

A basketball player has made 15 out of 25 free throws in practice. If they take 40 free throws in a game, how many do we expect them to make?

Experimental probability = 15/25 = 0.6

Expected makes = 0.6 × 40 = 24

Keep building this topic

Read this section alongside the surrounding pages in Expected Frequency. That gives you the full topic sequence instead of a single isolated revision point.

Practice Questions for Expected Frequency

Which formula correctly gives the expected frequency of an event?

  • A. Probability + Number of trials
  • B. Probability × Number of trials
  • C. Number of trials ÷ Probability
  • D. Probability ÷ Number of trials
1 markfoundation

A fair coin is flipped 50 times. The expected number of heads is 25. In the actual experiment, only 18 heads are recorded. Explain why the actual number of heads may differ from the expected number of heads.

3 markshigher

Quick Recall Flashcards

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.

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