Step 8 Objective

Use a single probability to find an estimate of frequency.

Examples of what pupils should know and be able to do

In a biased 1–12 spinner the probability of landing on a 5 is 0.2. Calculate the likely number of 5s in 500 spins.

Probing questions

How can you work out the likely frequency of an event if you know the probability?

What does the probability of 3/5 mean?

If the chance of event A is 5/12, how many times would you expect it to occur in 1000 outcomes?

What if pupils find this a barrier?

Ask pupils to predict the number of 1s when you roll a die 10 times, 20 times or 30 times. Use a spreadsheet to simulate the process and show that the relative frequency gets closer to probability multiplied by total number of rolls.