A同一个总体参数的两个无偏估计量,有更小方差的估计量更有效。() 发布时间:2017-06-13 10:04 │ 来源:www.tikuol.com 题型:判断题 问题: A同一个总体参数的两个无偏估计量,有更小方差的估计量更有效。()
题型:判断题 (2013·四川省乐山一模)The pupils were playing games in the classroom ________ a gunman entered and began shooting wildly at them.A.while B.whenC.as D.before 查看答案