Relative Frequency

When you actually run an experiment — tossing a coin, rolling a die, spinning a spinner — the relative frequency of an outcome is:

It is an experimental estimate of how likely the outcome is, usually written as a fraction, decimal or percentage.

For example, if a coin lands heads $30$ times in $50$ tosses, the relative frequency of heads is $\dfrac{30}{50} = 0.6$. The more trials you run, the closer the relative frequency tends to settle towards the true probability.

Worked example. A die is rolled $60$ times and shows a six on $12$ of them. Relative frequency of a six $= \dfrac{12}{60} = 0.2$.