A:7种
B:8种
C:9种
D:10种
阅读理解。
Hello! My nameis Alice. There are seven people in my family. My grandfather and grandmotherare in America. My parents are English teachers in China. I have two brothers.They are twins. We are students in the same school. I am in Grade One. They arein Grade Three.
下列图片能说明“巩固新生人民政权”这一主题的是( )
①一组数据不可能有两个众数;
②一组数据的方差必为正数,且方差越大,数据的离散程度越大;
③将一组数据中的每个数都加上同一个常数后,方差恒不变;
④在频率分布直方图中,每个长方形的面积等于相应小组的频率.
其中错误的个数有( )