The distribution function of the random variable is very difficult, and it is found online: Definition 2.1.2 is a random variable, which is any real number, the function is called the distribution function. The distribution function has the following properties: (1). (2) Monolecular no reduction, that is, if it is. (3) Right continuous, refers to it exists in any of the right limit of any, that is,. Conversely, there is a function of the above three properties, must be a distribution function of a random variable. (4). (1) What are the roles of the distribution function introduced into a random variable? For random variables, we must not only know which values, but also know the probability of taking these values; but therefore do not only know the probability of a value, but more importantly, you must know the probability of value in any limited interval, but Therefore, the distribution function describes the statistical regulation of random variables. On the other hand, the distribution function is a normal real value function, which is an object that we have already been familiar with in higher math. It has a relatively good nature. It has random variables and distribution functions as if random phenomena and higher teaching. A bridge that can be used to study the statistical law of random phenomenon with higher teaching methods. (2) Is the two distribution functions and still distributed? no. In fact, set to two distribution functions, but also, then. F (x) results, one is one number, is the value of the frequency (between 0, 1), the frequency of x
