题目

--- What has happened to Alice ?      --- I don’t know. She           her job.      A. can have lost       B. may have lost        C. should have lost    D. need have lost 答案：B在求两个变量x和y的线性回归方程过程中, 计算得="25," ="250," ="145," ="1380," 则该回归方程是                   .