Estimating an expected frequency Revision Card

AI generatedProbabilityKS3 / GCSE

Estimating an expected frequency.

Probability = favourable outcomes ÷ all outcomes when individual outcomes are equally likely.
A probability lies between 0 and 1; complementary probabilities sum to 1.
Experimental relative frequency estimates probability and can vary between samples.

Example 1

The probability of success is . Estimate the number of successes in 50 independent trials.

Expected frequency

Multiply the number of trials by the probability.

An expected frequency is a prediction, not a guaranteed count.

The probability of success is . Estimate the number of successes in 66 independent trials.

Expected frequency

Multiply the number of trials by the probability.

An expected frequency is a prediction, not a guaranteed count.

Question 1

The probability of success is . Estimate the number of successes in 84 independent trials.

Check answer

Expected frequency

Multiply the number of trials by the probability.

Question 2

The probability of success is . Estimate the number of successes in 104 independent trials.

Check answer

Expected frequency

Multiply the number of trials by the probability.

Question 3

The probability of success is . Estimate the number of successes in 126 independent trials.

Check answer

Expected frequency

Multiply the number of trials by the probability.

Question 4

The probability of success is . Estimate the number of successes in 150 independent trials.

Check answer

Expected frequency

Multiply the number of trials by the probability.

Question 5

The probability of success is . Estimate the number of successes in 80 independent trials.

Check answer

Expected frequency

Multiply the number of trials by the probability.