2. Mathematical expectation is that in probability theory and statistics, the expectation (or mathematical expectation, or mean, or expectation for short) of a discrete random variable is the sum of the probability of each possible result multiplied by its results in the experiment.
develop
Probability statistics is the application of probability theory to study the regularity of a large number of random phenomena; Give strict theoretical proof to the statistical methods obtained through a certain number of scientifically arranged experiments; And determine the applicable conditions of various methods, as well as the reliability and limitations of methods, formulas and conclusions. It enables us to judge whether a judgment can be guaranteed to be correct with a considerable probability from a group of samples, and can control the probability of error.
random phenomenon
From the random phenomenon, in nature and real life, some things are interrelated and constantly developing. In their relationship and development, according to whether there is an inevitable causal relationship, they can be divided into two distinct categories: one is deterministic phenomenon. The other is uncertainty.
Application of expected value
In statistics, when estimating the expected value of a variable, the common method is to measure the value of this variable repeatedly, and then use the average value of the obtained data as the estimation of the expected value of this variable.
In probability distribution, expected value and variance or standard deviation are important characteristics of distribution.
In classical mechanics, the algorithm of the center of gravity of an object is very similar to the algorithm of expected value.