【多选题】数字1.889小数点后修约成两位有效数位,修约后错误的为( )。
【单选题】________ with the question the students raised, the teacher paused for a few seconds. [ ]
【单选题】He__________from his seat and answered the question__________by the teacher.
【单选题】有一组数据如下:3、a、4、6、7,它们的平均数是5,那么这组数据的方差是 [ ]
【简答题】新闻一共有几个基本要素?分别是哪几个要素?
【单选题】有一组数据如下:3,a,4,6,7,它们的平均数是5,那么这组数据的方差是( )
【简答题】有一组数据如下:3,a,4,6,7,它们的平均数是5,那么这组数据的方差是( ) A.10 B. C.2 D.