Expected frequency (Edexcel GCSE Statistics): Flashcards
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Practise the cards
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What is the formula for expected frequency?
What is the formula for expected frequency?
Expected frequency = P(A) × number of trials
How do you find probability of an event?
How do you find probability of an event?
Probability = successful outcomes ÷ total outcomes
What is the probability of rolling >4 on a die?
What is the probability of rolling >4 on a die?
Probability = 2/6 = 1/3 (numbers 5 and 6)
What does expected frequency NOT tell you?
What does expected frequency NOT tell you?
It does not guarantee actual outcomes in real trials
Why must the expected frequency not exceed total trials?
Why must the expected frequency not exceed total trials?
It wouldn't make sense; can't expect more events than trials
What should you do if your expected frequency is very high?
What should you do if your expected frequency is very high?
Ensure it's reasonable — it can't be more than total trials
Key tip: How to handle fractions in calculations?
Key tip: How to handle fractions in calculations?
Use fractions directly without converting to decimals
Exam tip: Why check the reasonableness of your answer?
Exam tip: Why check the reasonableness of your answer?
To ensure the expected frequency makes sense given the trials
Expected rolls >4 in 150 dice rolls?
Expected rolls >4 in 150 dice rolls?
Expected = (1/3)×150 = 50 rolls
Expected heads in 80 fair coin flips?
Expected heads in 80 fair coin flips?
Expected = 1/2×80 = 40 heads