[Visitor (220.202.*.*)]answers [Chinese ]  Time :20230325  1. The random error term is a random variable with an expected value or average value of 0; 2. For all observations of explanatory variables, the random error term has the same variance; 3. The random error terms are not related to each other; 4. Explanatory variables are deterministic variables, not random variables, and are independent of each other with random error terms; 5. There is no precise (complete) linear relationship between explanatory variables, that is, the sample observation matrix of explanatory variables is a fullrank matrix; 6. The random error term obeys the normal distribution. 
