Relative frequency
An estimate of probability from an experiment: the number of times something happened divided by the total number of trials.
Last updated
Analogy
Like judging a weather pattern from last year's records.
Example
Relative frequency = 18 / 60 = 0.3In 200 spins, expect0.3 x 200 = 60 reds
In practice
Insurance firms use past records as relative frequencies to guess future risk.
Practice
Flashcards
- 18 reds in 60 spins. What is the relative frequency of red?0.3 (18 / 60).
Questions people ask
Why do more trials give a better estimate?
With few trials, luck can distort the results. With many trials, the relative frequency settles closer to the true probability. Flipping a coin 10 times might give 7 heads, but 1,000 flips will give close to 500. This idea is sometimes called the law of large numbers, and it is why casinos and insurers depend on big samples.
How do you predict how many times something will happen?
Multiply the probability by the number of trials. If the probability of red is 0.3 and you spin 200 times, you expect 0.3 x 200 = 60 reds. It is an estimate, not a guarantee. The more trials there are, the closer the actual number usually gets to your expected value.