We spend to much time calculating theoretical probability that we seldom take the time to work with relative frequency. We tell learners that as the sample size grow, the relative frequency will tend towards the theoretical probability, but do they actually understand it.
In this investigation we look at 2 events, picking a cards from a pack and looking at the favourite colours of learners. In the first case we all outcomes are equally likely so you can determine the probability. They draw a graph to help them visualise how the relative frequency tends towards the probability.
In the case of the second event, the outcomes are not equally likely, therefore we need to use the relative frequency to determine the probability. They draw a graph of the results to help them determine how big the sample have to be before we determine the probability.