一、要点分析1.随机变量若随机试验的结果可用一个变量表示,则这样的变量叫作随机变量,常用希腊字母ξ、η等表示.(1)随机变量的实质是随机试验结果的函数,它的自变量是随机试验的结果(是一个随机事件,不是量,更不是数);(2)随机变量的取值在试验前不可知,只有试验后才能知道;(3 First, the main point of analysis 1. Random variables If random test results can be represented by a variable, then such a variable is called a random variable, commonly used Greek letters ξ, η, etc. (1) The nature of random variables is a function of random test results, Its independent variable is the result of a random experiment (it is a random event, not a quantity, not a number); (2) The value of the random variable is unknown before the test and can only be known after the test; (3)