Expected frequency (AQA GCSE Statistics): Flashcards
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What is expected frequency in statistics?
What is expected frequency in statistics?
It's a prediction of how often an event occurs.
How do you calculate expected frequency?
How do you calculate expected frequency?
Use: Expected frequency = P(A) × number of trials.
What is P(A) in expected frequency formula?
What is P(A) in expected frequency formula?
P(A) is the probability of event A happening.
Example: Roll a die 60 times, expect number > 4?
Example: Roll a die 60 times, expect number > 4?
Expected frequency = 20 (P = 1/3 × 60).
Why is rounding important in expected frequency?
Why is rounding important in expected frequency?
You can't have fractional occurrences in reality.
What happens if trials are not independent?
What happens if trials are not independent?
Expected frequency formula may not apply correctly.
If P(A) = 0.25, expected frequency for 200 trials?
If P(A) = 0.25, expected frequency for 200 trials?
Expected frequency = 50 (0.25 × 200).
What should you check about probabilities?
What should you check about probabilities?
They must be between 0 and 1.
How does increasing trials affect actual results?
How does increasing trials affect actual results?
They get closer to expected frequency.
What is a common mistake in expected frequency problems?
What is a common mistake in expected frequency problems?
Not showing all working or miscalculating P(A).