relative frequency

Following an experiment, test or survey, we can use results to estimate probability.

We do this by using the following formula:

    \textmd{the experimental probability of an event} = \frac{\textmd{the number of times an event happens }}{\textmd{the total number of trials}}

The term for the estimate of the probability is relative frequency.

The table shows the results of throwing a dice 1000 times.

We can use these results to estimate the probability of getting a 6 each time the dice is thrown.

During 1000 throws, 6 has appeared 350 times.

In order to calculate the relative frequency, we must divide the number of times 6 has appeared, which is 350, by the number of trials, which is 1000. Therefore, the relative frequency of throwing a 6 is 350 ÷ 1000 = 0.35.