Estimating probability from experimental results Revision Card

AI generatedProbabilityKS3 / GCSE

Estimating probability from experimental results.

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

A spinner lands on red 12 times in 40 spins. Use these results to estimate .

Relative frequency = observed frequency ÷ total trials.

A spinner lands on red 14 times in 45 spins. Use these results to estimate .

Relative frequency = observed frequency ÷ total trials.

Question 1

A spinner lands on red 16 times in 50 spins. Use these results to estimate .

Check answer

Relative frequency = observed frequency ÷ total trials.

Question 2

A spinner lands on red 18 times in 55 spins. Use these results to estimate .

Check answer

Relative frequency = observed frequency ÷ total trials.

Question 3

A spinner lands on red 20 times in 60 spins. Use these results to estimate .

Check answer

Relative frequency = observed frequency ÷ total trials.

Question 4

A spinner lands on red 22 times in 65 spins. Use these results to estimate .

Check answer

Relative frequency = observed frequency ÷ total trials.

Question 5

A spinner lands on red 24 times in 70 spins. Use these results to estimate .

Check answer

Relative frequency = observed frequency ÷ total trials.