模型的假设: 5. Normality assumption: 8-N(,o) The properties of the OLSE: 5 b~N(b,2),bM的,03模型的假设： 5. Normality assumption: The properties of the OLSE: 5. 2 (0, )   i N 2 2 2 1 1 0 0 2 2 ˆ ˆ ( , ), ( , ) i i i X b N b b N b x x     