Step 9 Objective

Understand relative frequency as an estimate of probability and use this to compare outcomes of experiments.

Examples of what pupils should know and be able to do

Complete a relative frequency table from an experiment with two spinners.

Recognise that, with repeated trials, experimental probability tends to a limit.

Understand that relative frequency may be the only realistic way of estimating the probability, particularly when events are not equally likely.

Consider Real-life situations that have no theoretical probability, such as the chance of a plane crash, can only be judged based on the empirical evidence.

Consider how the probability changes in different circumstances, e.g. the chance that a drawing pin lands point up given different-shaped pins.

Probing questions

What value do you think this probability will become if we carry out the experiment 1000 times?

Why do you think the probability will settle on ...?

Imagine we are manufacturing cars. How could we find the probability of a person buying a car in October?

What if pupils find this a barrier?

Use the experiment of throwing a drawing pin and recording the number of times it lands point up.

Use computer software to simulate throwing two dice 50 times. Record the results and compare them with the expected results using a sample space diagram.