Frequency = frequency/sample capacity. Frequency can be expressed in fractions or decimals. Whether decimal places can be rounded off or not depends on the requirements of the topic.

Both decimals and fractions should be ok, but in mathematics, decimals are often used to express them. Frequency is an experimental value or a statistical value in use, which is random and can take multiple values. Therefore, it can only approximately reflect the probability of an event. Probability is a theoretical value, which is determined by the nature of the event, and can only take a unique value, which can accurately reflect the possibility of the event.

Extended data:

Introduce "probability" into the quantification of event possibility. Is there a stable value for the total number of independent repetitions n, event A frequency μ, event A frequency Fn(A)=μ/n, and event A frequency Fn(A)? If yes, the stable value p of the frequency μ/n is called the probability of the occurrence of event A, and it is recorded as P(A)=p (statistical definition of probability).

P(A) is objective, while Fn(A) depends on experience. In statistics, the value of Fn(A) is sometimes used as an approximation of probability when n is large.

Baidu encyclopedia-probability