Throw three dice at the same time and record the sum of the three dice.

A dice has six faces, and the number of points thrown may be 1~6.

∴ The possible value of the sum of three dice points is 3~ 18, which is the number of 16.

∴ Sample space = {3,4,5,6,7,8,9, 10, 12, 13, 14, 15.

Traditional probability

The traditional probability is also called Laplace probability because its definition was put forward by the French mathematician Laplace. If a random test contains a finite number of unit events, and the probability of each unit event is equal, then this random test is called Laplace test. In Laplace test, the probability P(A) of event A in event space S is:

For example, in the random experiment of throwing coins and dice at the same time, assuming that event A won the national emblem and the number of points was greater than 4, the probability of event A should be calculated as follows: S={ (national emblem, 1 minute), (number, 1 minute), (national emblem, 2 points), (number, 2 points).

According to Laplace's definition, the probability of A is 2/ 12= 1/6. I noticed some doubts in Laplace's experiment. In reality, is there an experiment whose unit event probability has exactly the same value, because people don't know whether the coin and the dice are "perfect", that is, whether the dice are made evenly, whether the center of gravity is located, and whether the roulette wheel is located.