A:①②③
B:②③④
C:②④⑤
D:①③⑤
请根据所给的词结合上下文的意思在下面短文的空格中填上适当的单词。
I am Liu Yun. I ____ in China. I like ____, ____ and ____ my bike. I have a new friend. She is Alice. She ____ ____ model ( 模 型) ships and ____ kites. Her father ____in a school. He is a teacher. He ____ to work ____ bus.
刹车时的车速(km/h)
0
10
20
30
40
50
60
刹车距离(m)
0.3
1.0
2.1
3.6
5.5
7.8
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( )