A: In a study, we observed and experimented with random phenomena. Under certain conditions, things of different nature may or may not appear. This kind of thing is called a random event, or event for short. Frequency refers to the number of times an event occurs in a certain category, also known as frequency, which is expressed by F. For example, in the experiment of a certain reaction, the number of times the event occurs in the whole reaction is called its number. For another example, if a class passes a test, how many * * * scores are 90 points, that is, 90 points is the number of times this event occurs.

The ratio of two numbers is called the ratio. When a molecule represents a part of the numerator (radix) of two numbers to be compared, the ratio is also called proportion, and percentage or percentage is another representation of proportion.

? ? Frequency, also known as relative times, refers to the number of times an event occurs divided by the total number of events, that is, the number of times a data appears divided by the total number of this group of data. Frequency is usually expressed in proportion or percentage.

Probability, also known as probability, is represented by the symbol p, which refers to the relative frequency of an event that can be expected in infinite observation, that is, the ratio of something or a situation appearing in the crowd. Probability is usually expressed in proportion. Some probabilities are known and some are unknown, but the frequency of events obtained through limited observation can be used as an estimate. If we know the probability of the event, we can know the possibility of the event in the experiment, so probability is a quantity that reflects the possibility of the event.