13.设 _(i)=(beta )_(0)+(beta )_(1)(x)_(i)+(e)_(i) =1, 2,···,n,试求β0和β1的最小二乘估计和σ^2的
参数 beta 的估计量 hat(beta) 具备有效性是指()A. $\text{var}(\hat{\beta})=0$B. $\text{var}(\ha
62.(多选题)对于分段线性回归模型Y_(i)=beta_(0)+beta_(1)X_(i)+beta_(2)(X_(i)-X^*)D_(i)+u_(i)，其中
[判断题] 估计线性回归方程中的回归参数β0、β1时，普遍采用的估计准则是最小二乘准则。（）A . 正确B . 错误
练习 已知A=[a_(1),a_(2),...,a_(m)],B=[beta_(1),beta_(2),...,beta_(m)]且PA=B,其中P是可逆矩阵,
4.(判断题) 向量组满足 beta_(1)=alpha_(1), beta_(2)=alpha_(1)+alpha_(2), beta_(3)=alpha_(
7.设alpha_(1),alpha_(2),alpha_(3),beta_(1),beta_(2)均为4维列向量，矩阵A=(alpha_(1),alpha_(
4.设向量组beta_(1)=alpha_(1)+2alpha_(2)-alpha_(3),beta_(2)=alpha_(1)+2alpha_(2)+2alp
设一元线性回归模型为_(i)=(beta )_(0)+(beta )_(1)(x)_(i)+(z)_(i)sim N(0,(sigma )^2),_(i)=(b
16.单选题设alpha_(1),alpha_(2)和beta_(1),beta_(2),beta_(3)是两个5维向量组，且两个向量组的秩相等，则（）A. 向